Question

Which of the following animals does not show any metamorphosis in the larval stage?
A.Pheretima posthuma
B.Asteria
C.Musca domestica
D.Butterfly

Answer 1

Hint: Metamorphosis is a biological process by which an animal physically develops after birth or hatching. This process involves a noticeable and relatively unexpected change in the animal's body structure through cell growth and differentiation.

Complete step by step answer:
-Metamorphosis is a process by which one form of an organism gets transformed into another form and finally develops into the adult form.
-After the birth or egg hatches, the organism forms the larvae which can be an elongated worm like structure.
-This larva develops to form pupa and then finally transforms to adult.
-There are many changes that occur in the body of the organism during development through various stages in the life cycle for example the cellular growth and differentiation that results in the formation of organs which performs different functions.
-Pheretima posthuma is the taxonomic name for earthworm which belongs to the phylum Annelida. These are elongated worms. They develop from the egg and form the larvae which develops directly to form the adult. There are no changes occurring in the body of earthworms or they do not form any structures while passing through the larval stage of the life cycle.

So, option A. Pheretima posthuma is the correct answer.

Note:
Progressive metamorphosis is seen in cases of Asteria, Musca domestica and Butterfly where adults are more advanced than the larva. Retrogressive metamorphosis is seen in cases of hemichordate where the larva of the animal is more advanced, having a notochord and nerve cord, than that of the adults.