Question

The author of the passage would probably agree with which of the following statements about the SCNs ?

• A. The SCNs are found in other organs and tissues of the body besides the hypothalamus.
• B. The SCNs playa critical but not exclusive role in regulating circadian rhythms.
• C. The SCNs control clock genes in a number of tissues and organs throughout the body.
• D. The SCNs are a less significant factor in regulating blood pressure than scientists once believed.
• E. The SCNs are less strongly affected by changes in light levels than they are by other external cues.

Answer 1

The correct option is B The SCNs playa critical but not exclusive role in regulating circadian rhythms.

"Four critical genes governing circadian cycles have been found to be active in every tissue, however, not just the SCNs, of flies, mice, and humans." This statement lends credibility to option B as the correct answer. The other choices do not fit the context as well as option B does.