Question

(3) An earthworm cannot lift its body upright. Why?​

Answer 1

$\bold\color{red}{Answer }$

An earthworm does not have bones. It has muscles which help to extend and shorten the body.

Answer 2

Explanation:

The hydraulic skeleton is the system of support found in soft-bodied invertebrates, which relies on the incompressibility of fluids contained within the body cavity. In earthworms, the coelomic fluid is under pressure within the coelom and therefore provides support for internal organs. Due to the hydraulic skeleton, during burrowing, the anterior end becomes turgid and aids in relaxation of longitudinal muscles.

So the correct answer is 'Coelomic fluid'.