Chapter 36 Reading
Identify the letter of the choice that best completes the statement or answers the question.
____ 1. An increase in Earth’s average temperature from the buildup of carbon dioxide and other gases in the atmosphere is called
____ 2. Organisms that obtain nutrients by breaking down wastes and dead organisms are called
____ 3. Nitrogen fixation is carried out primarily by
____ 4. As PCBs move up the trophic levels in food chains, or food webs, their concentration
____ 5. The total of the variety of living organisms in the biosphere is called