CBSE Class 10 Science 2020 · Paper 31/5/3 · Question 27(b)

(a) (i) Hydra: budding; (ii) Planaria: regeneration; (iii) Amoeba: binary fission; (iv) Spirogyra: fragmentation; (v) Rhizopus: spore formation. (b) Plants that have lost the capacity to produce seeds, such as banana, orange, rose and jasmine, can be grown by vegetative propagation; all the new plants are genetically similar to the parent plant and keep all its characteristics; plants raised this way bear flowers and fruits earlier than plants grown from seeds. (c) Fertilisation is the fusion of the male germ cell, produced by the pollen grain, with the female germ cell (egg) inside the ovule. The male germ cell can reach the egg only through a pollen tube, which grows from a pollen grain that has landed on the stigma and travels down the style to the ovule. If pollination does not occur, no pollen grain reaches the stigma, so no pollen tube forms, the male germ cell never reaches the egg, and fertilisation cannot take place.