Prelims

Biological Oxygen Demand (BOD) is a standard criterion for

Which one of the following is the best description of the term ‘ecosystem’?

Which one of the following is the correct sequence of a food chain?

Which one of the following is the process involved in photosynthesis?

With reference to the food chains in ecosystems, which of the following kinds of organism is/are
known as decomposer organism/organisms?
1.Virus
2.Fungi
3.Bacteria
Select the correct answer using the codes given below.

Which one of the following terms describes not only the physical space occupied by an
organism, but also its functional role in the community of organisms?

In the grasslands, trees do not replace the grasses as a part of an eological succession because
of

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

With reference to food chains in ecosystems, consider the following statements :
(1). A food chain illustrates the order in which a chain of organisms feed upon each other.
(2). Food chains are found within the populations of a species.
(3). A food chain illustrates the numbers of each organism which are eaten by others.
Which of the statements given above is/are correct?

Consider the following:
1. Photosynthesis
2. Respiration
3. Decay of organic matter
4. Volcanic action
Which of the above add carbon dioxide to the carbon cycle on earth?