Which of the following biomes has a structure made up primarily of the mineral deposits secreted by its dominant organisms
a. Coral reefs
b. Freshwater lakes
c. Rivers
d. Estuaries
e. Oceans

The open ocean and tropical rain forests contribute the most to Earth's net primary production because

a. Both have high rates of net primary production

b. Both cover huge surface areas of Earth

c. Nutrients cycle fastest in these two ecosystems

d. The ocean covers a huge surface area, and the tropical rain-forest has a high rate of production

Temperate forest in China and temperate forest in North America are part of the same biome but are distinct ecosystems. Explain.

Which statement best describes the desert biome?

a. It is found wherever temperatures are high

b. It contains a larger amount of biomass per unit area than any other biome

c. Its dominant vegetation is adapted to conserve water

d. Most are located at the equator; e. It is not suitable for human habitation

Compare the distribution of the natural terrestrial biomes of eastern North America with the distribution of anthropogenic biomes.

Changes in the seasons are caused by

a. The tilt of Earth's axis toward or away from the sun

b. Annual cycles of temperature and rainfall

c. Variation in the distance between Earth and the sun

d. An annual cycle in the sun's energy output

Like Earth, Mars has seasons—its Northern Hemisphere experiences winter when its Southern Hemisphere experiences summer. Which statement is the best explanation for seasonality on Mars?

a. Mars is tilted on its axis.

b. Mars has an elliptical orbit that brings it closer to the Sun in summer than in winter.

c. Mars has a circular orbit and maintains a constant distance from the Sun.

d. The Southern Hemisphere of Mars consistently receives direct solar radiation.

In an ecosystem, how is the flow of energy similar to that of matter, and how is it different?

What makes the Gobi Desert of Asia a desert?

a. The growing season there is very short

b. It is hot

c. Temperatures vary little from summer to winter

d. It is dry