Plants which produce characteristic pneumatophores and show vivipary belong to

Which of the following is a characteristic of a biological community?

When an organism moves away temporarily from a stressful habitat to a more hospitable area and returns when the stressful period is over,what is this process called?

In bacteria,fungi,and lower plants,various kinds of thick-walled spores are formed which help them to survive unfavourable conditions. This phenomenon can be called ...........

Assertion : Biotic community has higher position than population in ecological hierarchy.
Reason : Population of similar individuals remains isolated in the community.

Altitude sickness is an example of: