Which of the following structures functions to expel excess water from Paramecium cells?
a. cilia
b. trichocyst
c. pellicle
d. contractile vacuole
d
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Members of the genus Thermomonospora
A. can be isolated in compost piles and hay. B. produce single spores on their mycelia. C. spores can form on either aerial or substrate mycelia. D. All of the choices are correct.
Which of the following statements about the herbicide atrazine is false? a. Atrazine is used for weed control, mostly in cornfields
b. Atrazine from agricultural runoff persists in soil and water for decades. c. Atrazine causes or contributes to frog deformities. d. Male frogs exposed to atrazine at levels below those allowed in drinking water develop ovary tissue.
Local and long-distance signals in cells will trigger
changes in a. metabolism. b. gene expression. c. growth. d. development. e. any of these.
An Hfr cell and an F? cell result from conjugation between a donor cell and a recipient cell. Which statement is false regarding this event?
A. The donor could not have been F?. B. The donor could have been either F? or F+. C. The recipient could have been F?. D. The donor could have been Hfr.