Some organisms suspend their metabolic activities to survive in unfavourable conditions. Explain with the help of any four examples.

Explanation

(i) Poikilothermal animals like frogs and lizards undergo hibernation. (winter sleep).
(ii) Protopterus (African lungfish) undergoes aestivation (summer sleep) in a slime tube-like burrow.
(iii) Zooplanktons undergo diapause characterized by arresting of morphological growth and development during extreme summer period.
(iv) Thick walled and resistant spores are formed during unfavourable conditions in certain bactria, fungi and lower plants.