CBSE Class 10 Science 2019 · Paper 31/1/1/C · Question 18(a)

(a) Both reproduce by binary fission, in which one cell divides into two. In Amoeba the cell can split in any plane. In Leishmania, which has a whip-like flagellum at one end, binary fission occurs in a definite orientation in relation to this structure (lengthwise). (b) Regeneration is the ability of a fully differentiated organism to give rise to new individuals from its body parts; it is carried out by specialised cells that multiply and develop into the various cell types and tissues. When a Planaria is cut into pieces, each piece regrows the missing parts and develops into a complete Planaria (see the diagram). (c) The spores of Rhizopus are formed in sporangia, the blob-like structures at the tips of the hyphae. The thick-walled spores grow into new individuals when they come in contact with a moist surface, such as moist bread.