Almost all the nitrogen that enters the living world by natural means does so through the actions of _______. Nitrogen is then returned to the atmosphere by the actions of _______.
All the organisms at the first trophic level perform _______ and thus are referred to as _______. Any organism that feeds solely on first-trophic-level organisms would have to be a (choose one) carnivore/herbivore/omnivore.
All material produced by living things is capable of being broken down into its inorganic components by the class of living things called _______. This material is thus said to be _______.
There are fewer predator than prey animals due to drastic reductions of _______ at each _______.
Ozone is a gas composed entirely of the element _______ that reaches its greatest density in the layer of the atmosphere known as the _______ and that has the effect of keeping _______ from reaching Earth’s surface.
Most of the energetic short-wave radiation from the sun is transformed into _______, which can be trapped by greenhouse gases such as _______ and ________.
Global warming is certain to produce a _____ in global sea levels and a(n) _______ in precipitation in the United States.
The warm surface air of the tropics _______ as it rises, causing it to _______ moisture. At about 30° N and 30° S of the tropics, however, air descends and _______ moisture from the land.
Earth’s large vegetation regions are essentially defined by _______.
Starting at the North Pole and going south, list the order in which you would be likely to find the following biomes: temperate deciduous forest, tundra, tropical rainforest, taiga.
With increasing distance from the shoreline toward open sea, the abundance of marine life _______. With increasing distance from the ocean’s surface toward the ocean floor, the abundance of marine life _______.