Which statement best differentiates insects from arachnids?

Which statement best differentiates insects from arachnids?

• A. Insects have 3 body regions; arachnids have 2
• B. Insects have antennae; arachnids don't
• C. Insects have wings (some don't); arachnids don't
• D. Insects have eight legs

Answer: (B)

Antennal presence is the clearest way to tell these two apart. Insects always have a pair of antennae on the head, used for sensing their environment. Arachnids do not have antennae; they rely on other structures like pedipalps and body hairs for sensation. While wings can vary among insects (many are wingless) and arachnids never have wings, these are not universal or reliable differences. And insects have six legs, not eight, so the statement about eight legs is incorrect.

Antennal presence is the clearest way to tell these two apart. Insects always have a pair of antennae on the head, used for sensing their environment. Arachnids do not have antennae; they rely on other structures like pedipalps and body hairs for sensation. While wings can vary among insects (many are wingless) and arachnids never have wings, these are not universal or reliable differences. And insects have six legs, not eight, so the statement about eight legs is incorrect.