Chapter 46

In most ecosystems, the primary producers use energy from _________ to build organic compounds. a. sunlight b. heat c. breakdown of wastes and remains d. breakdown of inorganic substances in the habitat

Organisms at the lowest trophic level in a tallgrass prairie are all _________ . a. two steps away from the original energy input b. autotrophs d. both a and b c. heterotrophs e. both a and \(c\)

All organisms at the top trophic level _____________. a. capture energy from a nonliving source b. obtain carbon from a nonliving source c. would be at the top of an energy pyramid d. all of the above

Primary productivity is affected by _________. a. nutrient availability c. temperature b. amount of sunlight d. all of the above

Efficiency of energy transfers in aquatic ecosystems is typically higher than in land ecosystems because ____________. a. aquatic food webs include more endotherms b. algae do not make lignin c. primary production cannot occur in water d. all of the above

Most of Earth's fresh water is _____________. a. in lakes and streams c. frozen as ice b. in aquifers and soil d. in bodies of organisms

Earth's largest carbon reservoir is ____________. a. the atmosphere c. seawater b. sediments and rocks d. living organisms

Carbon is released into the atmosphere by ______________. a. photosynthesis c. burning fossil fuels b. aerobic respiration d. \(b\) and \(c\)

Greenhouse gases _____________. a. slow the escape of heat energy from Earth into space b. are produced by natural and human activities c. are at higher levels than they were 100 years ago d. all of the above

The ________ cycle is a sedimentary cycle. a. phosphorus c. nitrogen b. carbon d. water

Earth's largest phosphorus reservoir is _____________. a. the atmosphere c. sedimentary rock b. the ocean d. living organisms

Plant growth requires uptake of ________ from the soil. a. nitrogen d. both a and \(c\) b. carbon e. all of the above c. phosphorus

Nitrogen fixation converts _______ to ___________. a. nitrogen gas; ammonia d. ammonia; nitrates b. nitrates; nitrites e. nitrogen gas; nitrogen c. ammonia; nitrogen gas oxides

Burning fossil fuel releases ________ into the air. a. carbon dioxide c. phosphates b. nitrous oxide d. a and b

Match each term with its most suitable description. ____ carbon dioxide ____ nitrate ____ phosphate ____ nitrogen gas ____ bicarbonate ____ nitrous oxide a. contains triple bond b. mined from sedimentary rock c. marine carbon source d. soluble form of nitrogen e. greenhouse gas f. greenhouse gas and ozone destroyer