CBSE Class 10 Science 2022 · Paper 31/3/1 · Question 15

(a) Leishmania, which divides by binary fission in a definite orientation in relation to the whip-like structure (flagellum) at one end of its cell. It causes kala-azar. (b) Any two: plants raised by vegetative propagation bear flowers and fruits earlier than those produced from seeds; plants that have lost the capacity to produce seeds, such as banana, orange, rose and jasmine, can still be propagated; the new plants are genetically similar enough to the parent plant to have all its characteristics. (c)(i) Hydra reproduces by budding, using its regenerative cells. At one specific site on the body, repeated cell division produces an outgrowth called a bud. The bud develops into a tiny individual with its own mouth and tentacles, and when fully mature it detaches from the parent body and becomes a new, independent individual. OR (c)(ii) (I) The mature Spirogyra filament simply breaks up into smaller pieces (fragments), and each fragment grows into a new individual; this is fragmentation. (II) The bursting sporangium releases a large number of spores; protected by their thick walls, the spores grow into new Rhizopus individuals when they come in contact with a moist surface.