Which of the following is correct sequence of ecosystem in order of decreasing productivity?

Which of the following is the correct sequence of phases of Biotic succession ?

With reference to lichens, which of the following statements is/are correct? 1. Lichens are very good indicators of pollution. 2. Lichens grow well in polluted areas.

Which one of the following is most sensitive to environmental change?

Driving force of an ecosystem is:

Which of the following is NOT a biogeochemical cycle?