CBSE Class 10 Science 2022 · Paper 31/3/2 · Question 14

(a) Regeneration is the ability of a fully differentiated organism to give rise to new individuals from its body parts when it is cut or broken up, as in Planaria and Hydra. It is not the same as reproduction because it happens only after the body is cut up, and most organisms do not normally depend on being cut up in order to reproduce; reproduction is the normal way in which organisms produce new individuals. (b) Any two: plants raised by vegetative propagation bear flowers and fruits earlier than those raised from seeds; plants that have lost the capacity to produce seeds, such as banana, orange, rose and jasmine, can be propagated; all the plants produced are genetically similar enough to the parent to have all its characteristics. (c)(i) In Hydra a bud develops as an outgrowth due to repeated cell division at one specific site on the body. The bud grows, develops tentacles and a mouth, and becomes a tiny individual. When fully mature it detaches from the parent and becomes a new independent Hydra. OR (c)(ii) (I) The mature Spirogyra filament simply breaks up into two or more small pieces (fragments), and each fragment grows into a new individual; this is fragmentation. (II) The spores inside the sporangium are set free; protected by their thick walls, they are dispersed, and each spore that reaches a moist surface grows into a new Rhizopus individual; this is spore formation.