TEAS 7 Science Practice Test X3 learnexams

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TEAS 7 Science Practice Test X3 learnexams

Question 1: Experiments cannot validate hypotheses, only falsify them. The statement above can be restated in which of the following ways?

Options: A. Until disproved, an explanation for an observation is valid.
B. Certain concepts cannot be subjected to direct experimentation.
C. A hypothesis that has not been falsified remains provisional.
D. Proving a hypothesis exempts it from further testing.

Correct Answer: C. A hypothesis that has not been falsified remains provisional.

Explanation: Option C correctly captures the essence of the statement. It reflects the principle of falsifiability in scientific hypotheses: a hypothesis can never be conclusively proven, only tested and potentially falsified. If a hypothesis is not falsified, it remains a working model or provisional explanation until new evidence may disprove it.

Why Other Options Are Not Correct:

Option A: “Until disproved, an explanation for an observation is valid.” This option implies that an explanation is valid if not disproved, but it does not emphasize that validation is not possible—only falsification is the criterion. The original statement is more about the limits of validation rather than the validity of explanations.
Option B: “Certain concepts cannot be subjected to direct experimentation.” This does not directly address the concept of falsifiability. It discusses the feasibility of experimentation, which is a different issue from the validation or falsification of hypotheses.
Option D: “Proving a hypothesis exempts it from further testing.” This option is incorrect because it contradicts the principle of falsifiability. Hypotheses should always remain open to further testing and potential falsification rather than being considered exempt from scrutiny once proven.

Question 2: In which of the following regions of the body are the tibia and fibula?

Options: A. Coxal
B. Antecubital
C. Tarsal
D. Crural

Correct Answer: D. Crural

Explanation: Option D is correct because the tibia and fibula are located in the crural region, which corresponds to the lower leg.

Why Other Options Are Not Correct:

Option A: “Coxal” refers to the hip region, not where the tibia and fibula are located.
Option B: “Antecubital” refers to the region in front of the elbow, which is not related to the tibia and fibula.
Option C: “Tarsal” refers to the ankle region, where the bones of the foot are located, not the tibia and fibula.

Question 3: Which of the following functions does the myelin sheath perform for a nerve cell?

Options: A. Insulation
B. Regeneration
C. Sensory perception
D. Nutrition

Correct Answer: A. Insulation

Explanation: Option A is correct because the myelin sheath acts as an insulating layer around the nerve fibers, enhancing the speed and efficiency of electrical signal transmission along the nerve cells.

Why Other Options Are Not Correct:

Option B: “Regeneration” is not a function of the myelin sheath; it is more related to processes like nerve repair and regeneration.
Option C: “Sensory perception” is the function of sensory neurons, not directly of the myelin sheath.
Option D: “Nutrition” refers to the nourishment of cells, which is not a function of the myelin sheath.

Question 4: Which of the following occurs in an oxidation reaction?

Options: A. Removal of oxygen
B. Addition of carbon
C. Addition of neutrons
D. Removal of electrons

Correct Answer: D. Removal of electrons

Explanation: Option D is correct because oxidation involves the loss of electrons from a substance. This is a fundamental aspect of oxidation-reduction (redox) reactions.

Why Other Options Are Not Correct:

Option A: “Removal of oxygen” is not accurate for oxidation reactions, although oxidation reactions often involve oxygen, it is the loss of electrons that defines them.
Option B: “Addition of carbon” is not a characteristic of oxidation; oxidation reactions involve changes in electron count, not carbon addition.
Option C: “Addition of neutrons” is irrelevant to oxidation processes, which focus on electron transfer.

Question 5: To accurately measure the density of a series of small irregular solids made of plastic, wood, fibreglass, and glass, a student will need which of the following laboratory tools?

Options: A. Graduated cylinder, water, weighing balance
B. Graduated cylinder, spectrophotometer, water
C. Graduated beaker, metric ruler, water
D. Weighing balance, Bunsen burner, metric ruler

Correct Answer: A. Graduated cylinder, water, weighing balance

Explanation: Option A is correct because to measure density accurately, you need to determine both the mass (using a weighing balance) and the volume (using a graduated cylinder and water displacement method) of the irregular solids.

Why Other Options Are Not Correct:

Option B: “Graduated cylinder, spectrophotometer, water” is incorrect because a spectrophotometer is not used for measuring density.
Option C: “Graduated beaker, metric ruler, water” is less accurate for determining volume in irregular objects compared to a graduated cylinder.
Option D: “Weighing balance, Bunsen burner, metric ruler” is missing the critical tool for measuring volume (the graduated cylinder).

Question 6: Emphysema caused by damage to alveoli from toxins and pollutants is likely to result in the body having difficulty performing which of the following actions?

Options: A. Releasing histamine and acetylcholine
B. Exchanging oxygen and carbon dioxide
C. Absorbing food
D. Producing enzymes

Correct Answer: B. Exchanging oxygen and carbon dioxide

Explanation: Option B is correct because emphysema damages the alveoli, which are crucial for gas exchange in the lungs. This damage impairs the ability to exchange oxygen and carbon dioxide effectively.

Why Other Options Are Not Correct:

Option A: “Releasing histamine and acetylcholine” is unrelated to the function of the alveoli and their role in gas exchange.
Option C: “Absorbing food” is not affected by emphysema as it relates to digestion rather than respiratory function.
Option D: “Producing enzymes” is unrelated to the alveoli’s function in respiration.

Question 7: For which of the following reasons does a chloride ion have a negative charge?

Options: A. It gained an electron
B. It lost an electron.
C. It lost a proton.
D. It gained a proton.

Correct Answer: A. It gained an electron

Explanation: Option A is correct because a chloride ion has a negative charge due to gaining an extra electron, giving it an overall negative charge.

Why Other Options Are Not Correct:

Option B: “It lost an electron” would result in a positive charge, not a negative one.
Option C: “It lost a proton” would change the identity of the element rather than its charge.
Option D: “It gained a proton” would make the ion a positively charged species, not a negatively charged one.

Question 8: Which of the following substances is excreted by sweat glands in response to the breakdown of proteins and the formation of ammonia?

Options: A. Lysozymes
B. Urea
C. Water
D. Sebum

Correct Answer: B. Urea

Explanation: Option B is correct because urea is a major waste product of protein metabolism and is excreted by sweat glands, among other mechanisms, to help remove ammonia from the body.

Why Other Options Are Not Correct:

Option A: “Lysozymes” are enzymes involved in immune defense, not related to the breakdown of proteins or ammonia.
Option C: “Water” is a major component of sweat but does not specifically relate to the breakdown of proteins or ammonia.
Option D: “Sebum” is an oily substance secreted by sebaceous glands, not related to the breakdown of proteins or the formation of ammonia.

Question 9: The triple point of a substance is the temperature and pressure at which the substance exists as which of the following?

Options: A. Simultaneously in sol, gel, and plasma phases
B. As a gel with solid and liquid trapped in gas
C. As a sol with gas and solid trapped in liquid
D. Simultaneously in solid, liquid, and gas phases

Correct Answer: D. Simultaneously in solid, liquid, and gas phases

Explanation: Option D is correct because the triple point of a substance is defined as the unique temperature and pressure at which the substance can coexist in all three phases: solid, liquid, and gas.

Why Other Options Are Not Correct:

Option A: “Simultaneously in sol, gel, and plasma phases” does not accurately describe the triple point, which involves only solid, liquid, and gas phases.
Option B: “As a gel with solid and liquid trapped in gas” does not describe the triple point.
Option C: “As a sol with gas and solid trapped in liquid” does not accurately represent the concept of the triple point.

Question 1: A patient goes to the doctor with a cold and sore throat and asks for antibiotics. The doctor refuses to prescribe antibiotics to the patient because the illness is caused by which of the following pathogens?

Options: A. Fungus
B. Virus
C. Protist
D. Bacteria

Correct Answer: B. Virus

Explanation: Antibiotics are effective against bacterial infections, not viral ones. The common cold and sore throat are typically caused by viruses, such as rhinoviruses or coronaviruses. Since antibiotics do not affect viruses, they would not be appropriate for treating a viral infection.

Why Other Options Are Not Correct:

Option A: “Fungus” refers to fungal infections, which are treated with antifungal medications, not antibiotics.
Option C: “Protist” infections are rare compared to viral and bacterial infections and would be treated with antiparasitic medications.
Option D: “Bacteria” would be a target for antibiotics, but in this case, the illness is viral, making antibiotics ineffective.

Question 2: Which of the following is an efferent neuron that is responsible for releasing a neurotransmitter that stimulates a muscle cell to contract?

Options: A. Motor neuron
B. Interneuron
C. Sensory neuron
D. Neuroglia

Correct Answer: A. Motor neuron

Explanation: Motor neurons are responsible for transmitting signals from the central nervous system to muscles, causing them to contract. They are efferent neurons because they carry signals away from the brain and spinal cord to muscles and glands.

Why Other Options Are Not Correct:

Option B: “Interneuron” functions within the central nervous system to relay information between sensory and motor neurons but does not directly stimulate muscle cells.
Option C: “Sensory neuron” transmits sensory information from the body to the central nervous system, not to muscles.
Option D: “Neuroglia” (glial cells) support and protect neurons but do not directly stimulate muscle cells.

Question 3: Which of the following structures is present in both prokaryotic and eukaryotic cells?

Options: A. Endoplasmic reticulum
B. Cell membrane
C. Chloroplast
D. Golgi apparatus

Correct Answer: B. Cell membrane

Explanation: The cell membrane (or plasma membrane) is present in both prokaryotic and eukaryotic cells. It acts as a barrier that regulates what enters and exits the cell.

Why Other Options Are Not Correct:

Option A: “Endoplasmic reticulum” is found only in eukaryotic cells, not prokaryotic cells.
Option C: “Chloroplast” is present only in plant cells, which are eukaryotic, not in prokaryotic cells.
Option D: “Golgi apparatus” is also found only in eukaryotic cells, involved in modifying and packaging proteins and lipids.

Question 4: Which of the following actions allows for repolarization of a neuron?

Options: A. The inhibition of sodium and potassium pumps, stopping all ion movement into the neuron
B. The opening of sodium channels, allowing sodium to enter the neuron
C. The closing of both sodium and potassium channels to restrict movement of ions into and out of the neuron
D. The opening of potassium channels allowing potassium to leave the neuron

Correct Answer: D. The opening of potassium channels allowing potassium to leave the neuron

Explanation: Repolarization occurs when potassium channels open, allowing potassium ions to exit the neuron, restoring the negative internal charge relative to the outside.

Why Other Options Are Not Correct:

Option A: “Inhibition of sodium and potassium pumps” would not allow proper repolarization; the pumps are crucial for maintaining ionic gradients.
Option B: “Opening of sodium channels” leads to depolarization, not repolarization.
Option C: “Closing of sodium and potassium channels” without specific mention of potassium channels would not facilitate repolarization.

Question 5: Which of the following structures is an exocrine gland?

Options: A. Pineal gland
B. Parathyroid gland
C. Parotid gland
D. Pituitary gland

Correct Answer: C. Parotid gland

Explanation: The parotid gland is an exocrine gland that secretes saliva into the mouth through ducts. Exocrine glands release their products onto an epithelial surface.

Why Other Options Are Not Correct:

Option A: “Pineal gland” is an endocrine gland that secretes melatonin directly into the bloodstream.
Option B: “Parathyroid gland” is also an endocrine gland, releasing parathyroid hormone into the bloodstream.
Option D: “Pituitary gland” is an endocrine gland that releases hormones into the bloodstream.

Question 6: Which of the following is the function of a totipotent cell?

Options: A. Develops into any kind of cell
B. Fights infectious diseases
C. Aids in the maturation of sex cells
D. Carries electrical impulses

Correct Answer: A. Develops into any kind of cell

Explanation: Totipotent cells have the ability to differentiate into any type of cell in an organism, including extraembryonic tissues. They are the most versatile type of stem cell.

Why Other Options Are Not Correct:

Option B: “Fights infectious diseases” pertains to immune cells, not totipotent cells.
Option C: “Aids in the maturation of sex cells” is not a function of totipotent cells; it involves different cell types.
Option D: “Carries electrical impulses” relates to neurons, not totipotent cells.

Question 7: Which of the following classes of biological molecules includes enzymes?

Options: A. Lipids
B. Vitamins
C. Carbohydrates
D. Proteins

Correct Answer: D. Proteins

Explanation: Enzymes are proteins that act as biological catalysts, speeding up chemical reactions in cells.

Why Other Options Are Not Correct:

Option A: “Lipids” include fats and oils but do not include enzymes.
Option B: “Vitamins” are organic compounds that act as cofactors or coenzymes but are not enzymes themselves.
Option C: “Carbohydrates” are a class of molecules that include sugars and starches, not enzymes.

Question 8: Which of the following substances is responsible for donating H+ ions to act as a buffer when blood pH rises?

Options: A. Oxygen
B. Carbon monoxide
C. Carbon dioxide
D. Carbonic acid

Correct Answer: D. Carbonic acid

Explanation: Carbonic acid (H₂CO₃) acts as a buffer in the blood by donating H+ ions to help maintain pH balance. When blood pH rises, carbonic acid dissociates to release H+ ions.

Why Other Options Are Not Correct:

Option A: “Oxygen” is not involved in pH buffering.
Option B: “Carbon monoxide” is a gas with no role in buffering blood pH.
Option C: “Carbon dioxide” can convert to carbonic acid but does not directly donate H+ ions.

Question 9: Parasitic worm infestation is hypothesized to be damaging to the host. However, scientists have recently discovered that worm infestation can relieve the effects of certain autoimmune disorders. In which of the following ways should the hypothesis be modified, given the new findings?

Options: A. Worm infestation prevents the body from immune malfunction.
B. Worm infestation reduces the severity of certain autoimmune disorders.
C. Lack of worm infestations is the cause of some autoimmune disorders.
D. Worm infestations exacerbate the body’s immune reaction.

Correct Answer: B. Worm infestation reduces the severity of certain autoimmune disorders.

Explanation: Recent research suggests that parasitic worm infestations may have a modulatory effect on the immune system, potentially reducing the severity of autoimmune disorders by altering immune responses.

Why Other Options Are Not Correct:

Option A: “Worm infestation prevents the body from immune malfunction” is too broad and not specifically supported by the findings.
Option C: “Lack of worm infestations is the cause of some autoimmune disorders” is a hypothesis but not confirmed by the findings; it implies causation rather than correlation.
Option D: “Worm infestations exacerbate the body’s immune reaction” contradicts the new findings which suggest a beneficial effect.

Question 10: Which of the following best describes the result of using a catalyst in a chemical reaction?

Options: A. A more desirable product is often formed.
B. The reaction is completed in a shorter amount of time.
C. A greater amount of heat energy is released by the reaction.
D. The yield of product is increased.

Correct Answer: B. The reaction is completed in a shorter amount of time.

Explanation: A catalyst speeds up a chemical reaction by lowering the activation energy required. This leads to the reaction completing faster without being consumed in the process.

Why Other Options Are Not Correct:

Option A: “A more desirable product is often formed” is not a direct effect of a catalyst; it affects reaction rate, not product desirability.
Option C: “A greater amount of heat energy is released” is not necessarily affected by a catalyst.
Option D: “The yield of product is increased” may not be true; catalysts affect the rate, not necessarily the yield.

Question 11: An individual suffers severe blunt trauma to the thoracic cavity. Which of the following organs are at greatest risk from this injury?

Options: A. Heart and lungs
B. Brain and spinal cord
C. Liver and stomach
D. Large and small intestines

Correct Answer: A. Heart and lungs

Explanation: The thoracic cavity houses the heart and lungs, which are most directly at risk from blunt trauma to this area.

Why Other Options Are Not Correct:

Option B: “Brain and spinal cord” are protected by the skull and vertebral column, not located in the thoracic cavity.
Option C: “Liver and stomach” are located in the abdominal cavity, not directly in the thoracic cavity.
Option D: “Large and small intestines” are part of the abdominal cavity, not directly within the thoracic cavity.

Question 12: Which of the following is a component of the integumentary system that secretes pheromones?

Options: A. Fossa ovalis
B. Seminiferous tubule
C. Dermal papilla
D. Apocrine gland

Correct Answer: D. Apocrine gland

Explanation: The apocrine glands are a type of sweat gland that secretes pheromones, which are chemical signals used for communication between individuals.

Why Other Options Are Not Correct:

Option A: “Fossa ovalis” is a depression in the heart’s atrial septum, not related to pheromone secretion.
Option B: “Seminiferous tubule” is involved in sperm production in the testes, not pheromone secretion.
Option C: “Dermal papilla” is part of the skin’s structure but does not secrete pheromones.

Question 13: Which of the following processes causes most of the carbon dioxide from the blood to move into the alveoli?

Options: A. Passive transport using carrier proteins
B. Active transport using energy
C. Conversion to carbon monoxide
D. Diffusion down a concentration gradient

Correct Answer: D. Diffusion down a concentration gradient

Explanation: Carbon dioxide moves from the blood into the alveoli primarily by diffusion, following a concentration gradient from areas of higher concentration in the blood to lower concentration in the alveoli.

Why Other Options Are Not Correct:

Option A: “Passive transport using carrier proteins” is not how carbon dioxide is primarily transported to the alveoli.
Option B: “Active transport using energy” is not used for the movement of carbon dioxide in this context.
Option C: “Conversion to carbon monoxide” is incorrect as carbon dioxide is not converted to carbon monoxide in this process.

Question 14: Lipids absorbed in the small intestine will first enter which of the following structures?

Options: A. Veins
B. Arteries
C. Lacteal vessels
D. Interstitial spaces

Correct Answer: C. Lacteal vessels

Explanation: Lipids are absorbed by the lacteals, which are lymphatic vessels in the villi of the small intestine. From the lacteals, lipids enter the lymphatic system before reaching the bloodstream.

Why Other Options Are Not Correct:

Option A: “Veins” are part of the blood circulatory system and do not initially absorb lipids from the intestine.
Option B: “Arteries” also belong to the blood circulatory system and are not involved in lipid absorption.
Option D: “Interstitial spaces” are not involved in the direct absorption of lipids.

Question 15: Which of the following immune system molecules creates holes in the cell membranes of their target cells in order to destroy the cell?

Options: A. Perforins
B. Interferons
C. Cytokines
D. Lymphotoxins

Correct Answer: A. Perforins

Explanation: Perforins are proteins released by certain immune cells that create pores or holes in the target cell membranes, leading to cell destruction.

Why Other Options Are Not Correct:

Option B: “Interferons” are involved in antiviral defense and immune regulation but do not create holes in cell membranes.
Option C: “Cytokines” are signaling molecules that mediate immune responses but do not destroy cells directly.
Option D: “Lymphotoxins” are toxins produced by lymphocytes but are not the primary molecules creating holes in cell membranes.

Question 16: Which of the following properties does soap, an emulsifier, have that make it useful for washing dirt off one’s hands with water?

Options: A. Soap’s dual polar and nonpolar nature helps bond oil and water
B. Soap’s acidity causes grime to precipitate into the water
C. Soap’s enzymatic action helps to dissolve grime into small particles
D. Soap’s rough texture physically scours grime off surfaces

Correct Answer: A. Soap’s dual polar and nonpolar nature helps bond oil and water

Explanation: Soap molecules have both hydrophilic (polar) and hydrophobic (nonpolar) parts, allowing them to emulsify oil and grease in water, making it easier to wash them away.

Why Other Options Are Not Correct:

Option B: “Soap’s acidity” is not a primary factor in how soap works.
Option C: “Soap’s enzymatic action” is not involved in the cleaning process; soap works through emulsification.
Option D: “Soap’s rough texture” is not relevant; soap’s effectiveness comes from its chemical properties, not physical texture.

Question 17: The covalent bonds between the monomers of an enzyme macromolecule are:

Options: A. Ester bonds
B. Peptide bonds
C. Phosphodiester bonds
D. Glycosidic bonds

Correct Answer: B. Peptide bonds

Explanation: Enzymes are proteins, and the covalent bonds linking the amino acid monomers in proteins are peptide bonds.

Why Other Options Are Not Correct:

Option A: “Ester bonds” are found in lipids, not proteins.
Option C: “Phosphodiester bonds” are found in nucleic acids (DNA and RNA), not proteins.
Option D: “Glycosidic bonds” link sugars in carbohydrates, not amino acids in proteins.

Question 18: Which of the following is a protein present in blood plasma?

Options: A. Monocytes
B. Platelets
C. Fibrinogen
D. Lymphocytes

Correct Answer: C. Fibrinogen

Explanation: Fibrinogen is a blood plasma protein essential for blood clotting. It is converted into fibrin during the clotting process.

Why Other Options Are Not Correct:

Option A: “Monocytes” are a type of white blood cell, not a plasma protein.
Option B: “Platelets” are cell fragments involved in clotting, not proteins.
Option D: “Lymphocytes” are a type of white blood cell, not a plasma protein.

Question 19: Which of the following describes a genetic mutation that results in uncontrolled division of a single cell within the body?

Options: A. Cancer
B. Gene therapy
C. Stem cell
D. Translation

Correct Answer: A. Cancer

Explanation: Cancer is characterized by uncontrolled cell division due to genetic mutations. These mutations disrupt normal cell growth and division processes.

Why Other Options Are Not Correct:

Option B: “Gene therapy” involves altering genes to treat diseases but does not describe uncontrolled cell division.
Option C: “Stem cell” refers to cells with the potential to differentiate into various cell types but does not involve uncontrolled division.
Option D: “Translation” is the process of protein synthesis from mRNA, not related to uncontrolled cell division.

Question 1: Which of the following tools can be used to measure the turbidity of a liquid by measuring the transmission of light through the sample?

Options: A. Centrifuge
B. Spectrophotometer
C. Microdensitometer
D. Electrophorometer

Correct Answer: B. Spectrophotometer

Explanation: A spectrophotometer measures the intensity of light passing through a sample, which can be used to assess the turbidity of the liquid based on how much light is absorbed or scattered.

Why Other Options Are Not Correct:

Option A: “Centrifuge” separates substances based on density but does not measure light transmission or turbidity.
Option C: “Microdensitometer” measures optical density or thickness, but not specifically turbidity.
Option D: “Electrophorometer” is used for separating molecules based on their charge and size, not for measuring turbidity.

Question 2: A researcher wants to gather data on the average wing strength of all birds found in the American Northwest. The researcher only has one small net, so all large birds were excluded from the study. The researcher’s results were different than expected, but he believes his data include enough birds to estimate the strength of all birds. For which of the following reasons should this data be rejected?

Options: A. Data contradict the control group
B. Data were different than expected
C. Data are biased by the methodology
D. Data cannot be displayed graphically

Correct Answer: C. Data are biased by the methodology

Explanation: The exclusion of large birds introduces bias in the study, as the sample does not accurately represent the entire population of birds in the American Northwest. This bias affects the validity of the conclusions drawn.

Why Other Options Are Not Correct:

Option A: “Data contradict the control group” is not applicable as there is no control group mentioned.
Option B: “Data were different than expected” does not inherently indicate bias; unexpected results could still be valid if methodology is sound.
Option D: “Data cannot be displayed graphically” does not address the core issue of methodological bias.

Question 3: If a mother’s __________ cell contains mutated DNA, this mutation can be passed to her offspring. Which of the following options correctly completes the sentence above?

Options: A. Somatic
B. White blood
C. Germ
D. Stem

Correct Answer: C. Germ

Explanation: Germ cells (sperm and eggs) carry genetic information to offspring. Mutations in germ cells can be inherited by the next generation.

Why Other Options Are Not Correct:

Option A: “Somatic” cells are body cells that do not pass mutations to offspring.
Option B: “White blood” cells are a type of somatic cell and do not contribute to genetic inheritance.
Option D: “Stem” cells can differentiate into various cell types but mutations in these cells do not necessarily pass to offspring unless they are germ cells.

Question 4: The mitochondrial inner membrane carries out the same function in cellular respiration as the ________ membrane of chloroplasts in photosynthesis. Which of the following correctly completes the sentence above?

Options: A. Thylakoid
B. Epithelial
C. Nuclear
D. Tonoplast

Correct Answer: A. Thylakoid

Explanation: The mitochondrial inner membrane and the thylakoid membrane of chloroplasts are both involved in creating a proton gradient to generate ATP through chemiosmosis during cellular respiration and photosynthesis, respectively.

Why Other Options Are Not Correct:

Option B: “Epithelial” refers to a type of tissue, not a membrane involved in energy processes.
Option C: “Nuclear” membrane encloses the nucleus and is not involved in ATP synthesis.
Option D: “Tonoplast” surrounds the vacuole in plant cells and is not involved in energy generation.

Question 5: A study found two processes, Process A and Process B, to be correlated. Which of the following is true for these processes?

Options: A. The study indicates that Process A causes Process B
B. The study cannot indicate whether Process A and B have a positive relationship
C. The study does not indicate a causal relationship between the processes
D. The study cannot indicate whether Process A and B have a negative relationship

Correct Answer: C. The study does not indicate a causal relationship between the processes

Explanation: Correlation indicates a relationship or association between two variables but does not establish causation. Other factors could be influencing the observed correlation.

Why Other Options Are Not Correct:

Option A: Correlation alone does not imply causation; it cannot determine if one process causes the other.
Option B: Correlation indicates a relationship (positive or negative), but causation is not established.
Option D: Correlation does not specifically address whether the relationship is positive or negative, but rather indicates that a relationship exists.

Question 6: How many times stronger is the hydrogen-ion concentration of a pH 4 solution as compared with a pH 9 solution?

Options: A. 0.00001
B. 5
C. 100,000
D. 50

Correct Answer: C. 100,000

Explanation: The pH scale is logarithmic. The difference between pH 4 and pH 9 is 5 units. Since each pH unit represents a tenfold difference in hydrogen-ion concentration, a difference of 5 units corresponds to 105=100,00010^5 = 100,000105=100,000 times.

Why Other Options Are Not Correct:

Option A: “0.00001” is incorrect as it does not match the logarithmic scale difference.
Option B: “5” represents the pH difference but not the factor by which the concentration changes.
Option D: “50” is not correct as the factor change is based on powers of 10, not simple multiplication.

Question 7: Which of the following summarizes a change that takes place as a solid turns to a liquid?

Options: A. Particles have a decrease in mobility
B. Particles become less ordered
C. Particles move closer together
D. Intermolecular forces between particles become stronger

Correct Answer: B. Particles become less ordered

Explanation: As a solid melts into a liquid, the structured arrangement of particles becomes less ordered, and they move more freely.

Why Other Options Are Not Correct:

Option A: “Particles have a decrease in mobility” is incorrect; particles become more mobile in the liquid state.
Option C: “Particles move closer together” is incorrect; particles actually move further apart when transitioning to a liquid.
Option D: “Intermolecular forces between particles become stronger” is incorrect; these forces weaken to allow the solid to become a liquid.

Question 8: Genetic information describing the characteristics of an organism is found in which of the following?

Options: A. Nuclei
B. Membranes
C. Cilia
D. Ribosomes

Correct Answer: A. Nuclei

Explanation: Genetic information is stored in the DNA within the nucleus of eukaryotic cells.

Why Other Options Are Not Correct:

Option B: “Membranes” are not involved in storing genetic information.
Option C: “Cilia” are hair-like structures involved in movement, not genetic information.
Option D: “Ribosomes” are involved in protein synthesis, not storing genetic information.

Question 9: Which of the following organs filters excess solutes from the blood?

Options: A. Stomach
B. Spleen
C. Kidney
D. Gallbladder

Correct Answer: C. Kidney

Explanation: The kidneys filter excess solutes and waste products from the blood, which are then excreted as urine.

Why Other Options Are Not Correct:

Option A: “Stomach” is involved in digestion, not filtering blood.
Option B: “Spleen” filters blood but mainly focuses on removing old or damaged red blood cells and immune responses, not excess solutes.
Option D: “Gallbladder” stores bile, not involved in filtering blood.

Question 10: Which of the following is a function of bone?

Options: A. Storage of minerals
B. Detoxification of alcohol
C. Secretion of hormones
D. Production of otoliths

Correct Answer: A. Storage of minerals

Explanation: Bones store essential minerals such as calcium and phosphorus, which can be released into the bloodstream as needed.

Why Other Options Are Not Correct:

Option B: “Detoxification of alcohol” is a function of the liver, not bones.
Option C: “Secretion of hormones” is primarily a function of endocrine glands, not bones.
Option D: “Production of otoliths” pertains to the inner ear for balance, not bone function.

Question 11: Which of the following ions binds to the troponin complex, initiating the contraction of a muscle?

Options: A. Sodium
B. Potassium
C. Calcium
D. Phosphorus

Correct Answer: C. Calcium

Explanation: Calcium ions bind to the troponin complex on the actin filaments of muscle fibers, triggering muscle contraction by allowing myosin to interact with actin.

Why Other Options Are Not Correct:

Option A: “Sodium” is involved in action potentials but not in binding to troponin for muscle contraction.
Option B: “Potassium” also plays a role in action potentials but not in initiating muscle contraction.
Option D: “Phosphorus” is not directly involved in the contraction process mediated by troponin