How many mass extinctions were experienced on a global scale before the alarming mass extinction that's now occurring?
A) six
B) five
C) two
D) none
B
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Hypoglycemia, or low levels of glucose in the blood of a healthy human, is "corrected" by a(n) _____
A) increase in the secretion of insulin B) increase in the secretion of glucagon C) increase in the secretion of both insulin and glucagon D) decrease in the secretion of both insulin and glucagon E) increase in the secretion of thyroid hormones
Where would one expect to find the most telomerase?
A. male germ cells that give rise to gametes. B. skin cells from a 60-year-old individual. C. skin cells from a 2-year-old individual. D. a nerve cell from a 60-year-old individual. E. a nerve cell from a 2-year-old individual.
How many nucleotide bases does a codon consist of?
a. 3 b. 4 c. 6 d. 20 e. 64
Water draining from the land mixes with seawater
carried in on tides in which of the following? a. upper littoral b. midlittoral c. lower littoral d. estuary e. upwellings