Question

Which of the following animals shows regeneration of discarded parts?
A. Cockroach
B. Frog
C. Sparrow
D. Starfish

Answer 1

Regeneration occurs in organisms like a Hydra, flatworms, tapeworms, etc. They have highly adaptive regenerative capabilities. When an organism is wounded, their cells are activated and the damaged tissues and organs are regenerated back to the original state. Regeneration is the regrowth of the cut or discarded part of an organism on its own. It is seen mostly in animals, which have the totipotency ability.

Complete solution:
A. Cockroach: They can also survive terrible injuries in their nymph stages. The American cockroach has a strong capability of limb regeneration during the nymph stages. They cannot regenerate when they are matured.
B. Regeneration is restricted to the early stages of frog development. In mature or adult frogs the regeneration does not occur.
C. Sparrow does not have any regeneration ability.
D. In starfish, the totipotency is found in the central disc which requires 380 days for the regeneration of one complete arm when attached to the central disc. This central disc helps the regeneration of discarded parts in starfish. In starfish, regeneration takes place throughout life.
Hence, the correct answer is option D.

Note: Regeneration is two types. They are:
Morphallaxis: This type of regeneration has little growth and depends upon tissues repatterning. For example, Hydra grows by loss of cells from its end and by budding.
Epimorphosis: In this type of regeneration the cell involves dedifferentiation and growth with properly patterned structures. For example, regeneration of a vertebrate limb.