Which of the following characteristics do all insects exhibit? O they undergo complete metamorphosis and have segmented bodies O they have an exoskeleton or cuticle O they have jointed appendages and a radula O they have jointed appendages and spicules Submit Request Answer
The Correct Answer and Explanation is:
The correct answer is:
They have an exoskeleton or cuticle.
Explanation:
Insects belong to the phylum Arthropoda, a diverse group that includes organisms like spiders, crustaceans, and centipedes. One defining feature shared by all arthropods, including insects, is the presence of an exoskeleton, also called a cuticle. This is a rigid outer layer made primarily of chitin, a strong and flexible carbohydrate material. The exoskeleton provides protection, helps retain moisture, and offers support for muscle attachment—crucial for movement.
Other Characteristics of Insects:
- Three main body segments: head, thorax, and abdomen.
- Three pairs of legs (six legs total), all attached to the thorax.
- One pair of antennae.
- Compound eyes and sometimes simple eyes (ocelli).
- Most insects also have two pairs of wings, although some are wingless.
Why the Other Options Are Incorrect:
- “They undergo complete metamorphosis and have segmented bodies”:
While it is true that insects have segmented bodies, not all insects undergo complete metamorphosis (which includes four stages: egg, larva, pupa, adult). Some insects undergo incomplete metamorphosis (egg, nymph, adult). For example, grasshoppers and dragonflies do not pass through a pupal stage. - “They have jointed appendages and a radula”:
Insects do have jointed appendages, which is a trait of arthropods. However, the radula is a structure found only in mollusks like snails. It is a toothed, chitinous ribbon used for scraping food—not found in insects. - “They have jointed appendages and spicules”:
Again, jointed appendages are correct, but spicules are structures found in sponges (phylum Porifera), not in insects. Spicules provide structural support in sponges, not in arthropods.
In conclusion, the exoskeleton or cuticle is the only characteristic in the list that all insects universally possess, making it the best and most accurate answer.