In which of the following animals are bones not present?
(a)Earthworm
(b)Snail
(c)Cockroach
(d)All of the above

Hint: Invertebrates don't possess a skeleton of bone, either internal or external. They include hugely varied body plans. The most characteristic of all invertebrates is that they lack a backbone. They do not have any bones in the least.

Complete answer:
Earthworms don't have a backbone. They fall into the category of invertebrates. They do not have bones, legs, eyes, or teeth. A cockroach has six legs, three body segments, and no bones. it's an exoskeleton in situ of a skeleton. The endoskeleton is tough and shell-like and covers its body. Snails haven't any bones or rings or joints in their bodies. Thus all of the above-given animals are invertebrates and thus they are devoid of bones.

Additional Information: A backbone is a component of a skeleton of bone which grows inside many animals, like fish, birds and mammals. Most animals don't have a skeleton of bone inside them so that they don't have a backbone. These animals are called invertebrates. Invertebrates like worms and snails have a skeleton of water inside their body. Hence invertebrates lack a backbone.

So, the correct answer is, “All of the above”.

Note: Characteristics of Invertebrates;
An invertebrate is an animal that has all of the subsequent characteristic features at some point in its life:
-They do not have a backbone.
-They are multicellular.
-They have no cell walls, like all other animals.
-They reproduce by two reproductive cells, or gametes, coming together to produce a new organism of their species.