c) Unicellular organisms respire and reproduce
The unicellular organisms respire aerobically or anaerobically. They do not have any respiratory structures for respiration. They respire by the process of diffusion through the skin surface.
Unicellular organisms reproduce by the following ways:
- The unicellular organisms reproduce by binary fission. In this, a single cell divides, giving rise to two daughter cells. This can be seen in bacteria and amoeba.
- The yeast cells reproduce by the process called budding.
- Sometimes amoeba reproduces by the process called encysting. During unfavourable conditions, it forms a protective covering around itself called a cyst. This cyst contains chitin that helps it to reproduce.