Toxic elements such as mercury are found in
the human body because
a. of contamination from the environment.
b. trace amounts of these elements have vital
biological functions.
c. they are needed to kill bacteria.
d. they may be ingested with food but
inactivated by cells.
e. in small amounts they are biologically
inactive and tolerated by cells.
A
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What will be an ideal response?
The North American bison was hunted to near extinction in the 1800s, and has since recovered, but with decreased genetic diversity. This is an example of
A. gene flow. B. increased mutation rate. C. a bottleneck effect. D. natural selection. E. a founder effect.
If the frequencies of recessive and dominant alleles in a population do not change over time, that population
a) is evolving b) is migrating c) is exhibiting genetic drift d) is in Hardy-Weinberg equilibrium e) will soon be extinct
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A. Volcanic activity B. Anaerobic microbial activity C. Respiration D. Fuel combustion E. All of the above.