Answer the following questions :(a) Define vestigial organs.(b) Write names of any two vestigial organs in human body.(c) Write the names of any two vestigial organs which are non-functional in human beings but functional in other organisms.

Answer:

(a) Vestigial organs are degenerated or underdeveloped, useless organs present in an organism, which were well developed and functional in its ancestors. They are an evidence of evolution.

(b) The vermiform appendix and the muscles of the ear pinna. (Also: tail bone (coccyx), wisdom teeth, body hair.)

(c) (1) The appendix — useless in man but fully functional in ruminants (and in herbivores such as the rabbit), where it helps in digestion of cellulose. (2) The muscles of the ear pinna — useless in man but functional in monkeys, which move their ear pinna. (Also: the nictitating membrane, functional in birds and frogs for protecting the eye.)