Estimates vary, but reasonable numbers for extinction rates suggest that extinction is occurring at a rate approximately
____ times above the normal background rate.
a. 10
b. 100
c. 1000
d. 10,000
e. 1,000,000
c
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European explorers sailing across the Pacific leave several pairs of pigs on a remote island with the intention of visiting again in future years to harvest fresh meat. This would most resemble a case of artificially induced allopatric speciation through:
A. vicariance. B. dispersal.
Parietal cells secrete pepsinogen. Indicate whether the statement is true or false
How many hydrogen bonds exist between a G-C base pair?
A) 1 B) 2 C) 3 D) 4
Please match the virulence factor of Streptococcus pyogenes to its description.
Hyaluronidase A) Surface antigen that serves as the basis for alphabetical grouping; protects bacterium from lysozyme B) Toxin that causes beta-hemolysis on blood agar and injures cells of the host C) Enzyme that plays a role in invasion by leading to the digestion of fibrin clots D) Projecting surface antigen that facilitates adherence and resists phagocytosis E) Chemical surface layer that prevents an immune response by the host F) Enzyme that promotes invasion into tissues by breaking down the binding substance in connective tissues