Recently biologists have been interested in a tide-associated periodic behavior displayed by the diatom Hantzschia
This is not to suggest that the period of this biological clock is immutably fixed. Biologists have concluded that even though a diatom does not rely on the environment to keep time, environmental factors—including changes in the tide’s hydrostatic pressure, salinity, mechanical agitation, and temperature—can alter the period of its biological clock according to changes in the tidal cycle. In short, the relation between an organism’s biological clock and its environment is similar to that between a wristwatch and its owner: the owner cannot make the watch run faster or slower, but can reset the hands. However, this relation is complicated in intertidal dwellers such as commuter diatoms by the fact that these organisms are exposed to the solar-day cycle as well as to the tidal cycle, and sometimes display both solar-day and tidal periods in a single behavior. Commuter diatoms, for example, emerge only during those low tides that occur during the day.
According to the passage, the periodic behavior displayed by commuter
A. Greater unpredictability than the corresponding behavior under natural conditions
B. A consistent periodic schedule in the short term
C. No difference over the long term from the corresponding behavior under natural conditions
D. Initial variability caused by the constant conditions of the laboratory
E. Greater sensitivity to environmental factors than is the case under natural conditions
- Many Runagian senior citizens are no better off financially now than they were before the increase.The phrase “better off” is closest in meaning to________?
- The word "accidental" is closest in meaning to___________ ?
- Who can it be? I’ m quite ____ a loss to guess．
- The number of people flying first class on domestic flights rose sharply in 1990, doubling the increase of the previous year.
- The word "conspicuous" is closest in meaning to______ ?