Question

Two Animal Phyla have exoskeletons: Arthropods and _____. This trait is: [homologous | analogous]

1) Echinodermata : homologous
2) Mollusca : analogous
3) Echinodermata : analogous
4) Mollusca : homologous

Answer 1

The correct answer is 2) Mollusca : analogous. This signifies that both mollusks and arthropods developed exoskeletons independently, and these exoskeletons have different compositions and evolutionary origins.

Step-by-step explanation:

Two Animal Phyla have exoskeletons: Arthropods and Mollusca. This trait is analogous, meaning that the trait evolved independently in these two phyla rather than from a common ancestor. The correct answer is 2) Mollusca : analogous.

While arthropods are known for their chitinous exoskeletons, mollusks have a very different exoskeleton made up of a calcareous shell. Unlike arthropods, mollusks do not undergo molting, another difference highlighting that their exoskeletal trait is analogous. This contrast distinguishes the adaptations of these two diverse taxa in the face of evolutionary pressures.