What percentage of the earth's topsoil is lost to erosion each year?
A) 0.1 %
B) 1%
C) 10%
D) 50%
E) 100%
Ans: B) 1%
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A chemical that denatures proteins is MOST likely to be classified as a(n) ________ agent
A) antiseptic B) bacteriostatic C) bacteriocidal D) detergent
Which statement(s) about the rII- strain of T4 bacteriophage that Benzer studied is (are) true? (Select all that apply.)
A) It grows in E. coli B, but not in E. coli K(?). B) It produces larger plaques than wild-type. C) It grows in E. coli K(?), but not in E. coli B. D) It produces smaller plaques than wild-type.
Proton pumps are used in various ways by members of every domain of organisms: Bacteria, Archaea, and Eukarya. What does this most probably mean?
A) Proton gradients across a membrane were used by cells that were the common ancestor of all three domains of life. B) The high concentration of protons in the ancient atmosphere must have necessitated a pump mechanism. C) Cells of each domain evolved proton pumps independently when oceans became more acidic. D) Proton pumps are necessary to all cell membranes.
Caulobacter produce free-swimming ________ cells for dispersal that must differentiate into _______ cells for reproduction
a. stalked / swarmer b. peritrichous / planktonic c. swarmer / stalked d. persister / dormant