Q.Which of the following is the period between birth and death?

The time between birth and death of an organism is called its life span.

Life span is the duration of existence of an individual organism, measured from its birth (or origin) to its natural death. It varies enormously among organisms — from a few days (e.g. a mayfly) to many hundreds of years (e.g. some trees and a giant tortoise). It should …

Hydra is considered biologically immortal because its stem-cell-driven continuous tissue renewal means it does not show the signs of ageing seen in most animals.

This fact belongs to the pre-rationalisation chapter "Reproduction in Organisms," which is no longer part of MP's current NCERT-aligned syllabus (the given chapter menu does not include it), so it is flagged out of syllabus. For completeness: Hydra, a simple freshwater cnidarian, possesses populations of actively dividing interstitial (stem) cells throughout its body column that continuously replace ageing/damaged cells. Because of this constant self-renewal (and its strong regenerative capacity — a whole animal can regrow from a small fragment), Hydra shows negligible se …

Bamboo is monocarpic — it flowers only once, sets seed, and then the plant dies.

Plants are classified by how many times in their lifetime they flower and fruit:

• Monocarpic plants flower and fruit only once in their lifetime, after which the whole plant dies. Bamboo species are the classic textbook example — a bamboo clump may grow vegetatively for many years (even decades) before flowering gregariously just once, setting seed, and then dying. …