Humans have dramatically altered the rate of nitrogen fixation into forms usable by autotrophs by ________
A) burning of fossil fuels to meet our energy needs
B) using antibiotics to reduce the numbers of denitrifying bacteria
C) selectively removing leguminous plants
D) producing synthetic fertilizers and applying them to crops, lawns, and parks
E) increasing the erosion of farmlands through poor agricultural practices
Answer: D
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Which of the following is not considered a visual variable in symbolization?
A. pattern B. color C. diagram D. size E. shape
Environmental protection has been proven to ________ the number of available jobs because ________.
A. Stabilize; the use of nonrenewable resources is stabilized, and jobs are scarce anyway B. Stabilize; it limits the use of nonrenewable resources (as in the case of the logging industry) C. Decrease; it limits the use of nonrenewable resources (as in the case of the logging industry) D. Decrease; it negatively affects economic growth E. Increase; labor is usually substituted for natural resources (as in the case of recycling)
Which of the following is likely responsible for algae bloom in lakes and streams?
A) increased carbon and magnesium B) increased nitrogen and phosphorus C) increased methane and hydrogen D) increased mercury through biomagnification E) increased potassium and carbon monoxide
If you remove two protons and two electrons from a sulfur atom (S), what new element is formed?
A. Si+2 B. Ar-2 C. Al D. Si E. Al+2