Opening of the stomata:a
occurs during prolonged periods of drought.
b. occurs when there is a high concentration of carbon dioxide in the leaf.
c. is under hormonal control.
d. is triggered by darkness.
e. is controlled by the changes in shape of the companion cells.
C
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All of these are reported to cause deformities in amphibians except:a
pesticides. b. pollution. c. trematodes. d. atrazine. e. predators
Which of the following statements is true about the phylogenetic tree shown here?
A. The gibbon is more closely related to the rhesus monkey than to the chimpanzee. B. The galago is more closely related to the green monkey than to the capuchin. C. The green monkey and rhesus monkey share a common ancestor with the gibbon and chimpanzee. D. The gibbon does not share a common ancestor with the chimpanzee or human. E. The green monkey and rhesus monkey share a more recent common ancestor than do the chimpanzee and human.
In a small group of people living in a remote area, there is a high incidence of blue skin, a condition that results from a variation in the structure of hemoglobin. All of the blue skinned residents can trace their ancestry to one couple, who were among the original settlers of this region. The unusually high frequency of blue skin in the area is an example of
A. mutation B. genetic drift C. natural selection D. sexual selection E. heterozygote advantage
Two bird species have different mating calls, occupy different habitats in nature, and when they hybridize, the hybrids are infertile. Which isolating mechanisms maintain these species?
A. geographical isolation, temporal isolation, behavioral isolation B. mechanical isolation, hybrid sterility, geographical isolation C. ecological isolation, mechanical isolation, hybrid sterility D. ecological isolation, behavioral isolation, and hybrid sterility