(i)
| BINARY FISSION |
MULTIPLE FISSION |
| a. It occurs during favourable condition |
a. It occurs during unfavourable condition. |
| b. The parent cell divides first through karyokinesis followed by cytokinesis and two daughter cells are produced |
b. The parent cell divides continuously through karyokinesis and cytokinesis does not occur immediately. Many daughter nuclei are formed in the parent cell |
| c. There is no cyst formation. |
c. The parent cell forms the cyst to protect the daughter nuclei, which is broken when the favourable conditions return |
| d. Example: occurs in prokaryotes such as bacteria, amoeba, Euglena etc. |
d. Example: in protists and in some parasitic species such as plasmodium, sporozoans, algae etc. |
(ii) Vegetative propagation is practised for growing some types of plants because of following advantages:
a. It helps to introduce plants in new areas where seed germination fails to produce mature plants due to changes in environmental factors and the soil.
b. It is more rapid, easier and cheaper method.
c. Produces identical quality as the parent.
d. Faster and more certain method of propagation.
For example: tuber of potato, the rhizome of ginger etc.
(iii) DNA copying is an essential part of the reproduction process because an organism’s entire genetic information is contained within the DNA. If the DNA mutates, then there is a chance that the resulting organism may be born with a deformity or other genetic abnormality.
