Identify the tone of the passage.
In nearly all human populations, a majority of individuals can taste the artificially synthesized chemical phenylthiocarbonide (PTC). However, the percentage varies dramatically—from as low as 60 percent in India to as high as 95 percent in Africa. That this polymorphism is observed in nonhuman primates as well indicates a long evolutionary history which, although obviously not acting on PTC, might reflect evolutionary selection for taste discrimination of other, more significant, bitter substances, such as certain toxic plants.
A somewhat more puzzling human polymorphism is the genetic variability in earwax, or cerumen, which is observed in two varieties. Among European populations, 90 percent of individuals have a sticky yellow variety rather than a dry, gray one, whereas in northern China these numbers are approximately the reverse. Perhaps like PTC variability, cerumen variability is an incidental expression of something more adaptively significant. Indeed, the observed relationship between cerumen and odorous bodily secretions, to which nonhuman primates—and to a lesser extent humans—pay attention suggests that during the course of human evolution genes affecting body secretions, including cerumen, came under selective influence.
Identify the tone of the passage.
In nearly all human populations, a majority of individuals can taste the artificially synthesized chemical phenylthiocarbonide (PTC). However, the percentage varies dramatically—from as low as 60 percent in India to as high as 95 percent in Africa. That this polymorphism is observed in nonhuman primates as well indicates a long evolutionary history which, although obviously not acting on PTC, might reflect evolutionary selection for taste discrimination of other, more significant, bitter substances, such as certain toxic plants.
A somewhat more puzzling human polymorphism is the genetic variability in earwax, or cerumen, which is observed in two varieties. Among European populations, 90 percent of individuals have a sticky yellow variety rather than a dry, gray one, whereas in northern China these numbers are approximately the reverse. Perhaps like PTC variability, cerumen variability is an incidental expression of something more adaptively significant. Indeed, the observed relationship between cerumen and odorous bodily secretions, to which nonhuman primates—and to a lesser extent humans—pay attention suggests that during the course of human evolution genes affecting body secretions, including cerumen, came under selective influence.
The correct option is A Arcane
The passage is difficult to understand and comprehend. Therefore, arcane, which means understood by a few, is the correct tone for the passage.
Caustic meaning harsh or critical is not the correct tone.
Biased meaning favouring one person or group over the other is also not the correct tone.
Apologetic meaning to express remorse or guilt is also not the correct tone.
Hence, the correct answer is option A.
The passage is difficult to understand and comprehend. Therefore, arcane, which means understood by a few, is the correct tone for the passage.
Caustic meaning harsh or critical is not the correct tone.
Biased meaning favouring one person or group over the other is also not the correct tone.
Apologetic meaning to express remorse or guilt is also not the correct tone.
Hence, the correct answer is option A.
