Unlike eutherians, both monotremes and marsupials A) lack nipples B) have some embryonic development outside the uterus ) lay eggs are found in Australia and Africa 23) All animals, whether large or small, have ? A) an external body surface that is dry basic body plan that resembles a two-layered sac a body surface covered with hair to keep them warm D) most of their cells in contact with an aqueous medium 24) Connective tissues typically have A) little space between the membranes of adjacent cells B) the ability to transmit electrochemical impulses -‘ he ability to shorten upon stimulation D) relatively few cells and a large amount of extracellular matrix 25) Most types of communication between cells utilize_ A) the exchange of cytosol between the cells B) the movement of the cells C) chemical or electrical signals the exchange of DNA between the cells
The Correct Answer and Explanation is :
Here are the answers with explanations:
23) All animals, whether large or small, have:
- D) most of their cells in contact with an aqueous medium
Explanation:
This is because all animals, regardless of size, have cells that function best when immersed in an aqueous environment, as water is essential for the biochemical processes that occur inside cells. Animals’ tissues and organs are bathed in bodily fluids (such as blood, lymph, or extracellular fluid), which are largely water. Water also aids in nutrient and gas exchange, waste removal, and the maintenance of cellular homeostasis.
24) Connective tissues typically have:
- D) relatively few cells and a large amount of extracellular matrix
Explanation:
Connective tissues are characterized by a sparse arrangement of cells that are embedded in a substantial amount of extracellular matrix (ECM). The ECM is composed of fibers (such as collagen, elastin) and ground substance, providing structure, strength, and support to tissues and organs. The cells in connective tissues (like fibroblasts, osteocytes, and chondrocytes) produce and maintain the ECM. This contrasts with epithelial tissues, where cells are closely packed together.
25) Most types of communication between cells utilize:
- C) chemical or electrical signals
Explanation:
Cell communication primarily occurs through chemical or electrical signals. Chemical signaling involves the release of molecules like hormones or neurotransmitters, which bind to receptors on the surface of target cells, initiating a response. Electrical signals are important in excitable cells (like neurons and muscle cells), where changes in membrane potential facilitate the transmission of information. These types of signaling are crucial for the coordination of complex processes like growth, immune response, and neural communication.
For the first question:
Monotremes and marsupials are distinct from eutherians (placental mammals) in several key ways:
- A) lack nipples is incorrect because monotremes have mammary glands that secrete milk, though they don’t have nipples, while marsupials do have nipples.
- B) have some embryonic development outside the uterus is true, especially for monotremes, as they lay eggs. Marsupials give birth to underdeveloped young, and they continue developing in a pouch.
- C) lay eggs is correct for monotremes, which include species like the platypus and echidna, but marsupials give birth to live young.
- D) are found in Australia and Africa is inaccurate as only marsupials are primarily found in Australia, with monotremes being limited to Australia and New Guinea.
So the most accurate answer is C) lay eggs for monotremes.