Define the following processes of asexual reproduction :
(i) Spore formation, (ii) Regeneration, (iii) Multiple fission.

Explanation

(i) Spore formation is a common method of asexual reproduction in many lower forms of life, like bacteria, fungi etc. It occurs mostly during unfavourable conditions such as extreme heat, dryness etc. The spores are asexual reproducing bodies enclosed in a thick walled structure called sporangium. On return of favourable conditions the sporangium wall bursts and the spores are released.
(ii) Regeneration means renewal, restoration, and growth. The process of getting back a full organism from its body parts is called regeneration. Some organism like Hydra, Planaria have the capability to develop a whole new organism from its cut body parts. Regeneration of an organism occurs by the process of growth and development. Regeneration occurs in those organisms which have relatively simple body organization consisting of few specialized cells.
(iii) In multiple fission, the nucleus divides several times simultaneously or successively into a number of daughter nuclei and then the cytoplasm divides into as many cells as there are nuclei, each cell containing a nucleus. It is the common form of asexual reproduction in certain acellular organisms.