Question

3 which statement is true about earthworms? a earthworms have neither an endoskeleton nor an exoskeleton. b earthworms have both an endoskeleton and an exoskeleton. c earthworm skeletons are made of cartilage. d earthworm skeletons are made of muscle.

Explanation:

Earthworms belong to annelids. Annelids have a hydrostatic skeleton (relying on fluid - filled cavities for support), and they do not have endoskeletons (like those in vertebrates, made of bone or cartilage) or exoskeletons (like those in arthropods, a hard outer covering). So option A is correct because earthworms indeed have neither an endoskeleton nor an exoskeleton. Option B is wrong as earthworms can't have both types of skeletons. Option C is wrong because earthworms don't have skeletons made of cartilage. Option D is wrong because earthworms' hydrostatic skeleton is not made of muscle (muscle works with the fluid - filled cavity in the hydrostatic skeleton system, but the "skeleton" part is the fluid - filled structure, not muscle as a skeletal material).

Answer:

A. Earthworms have neither an endoskeleton nor an exoskeleton.