专业八级改错练习 第111期

The term biological clock is applied to the means which living __1__
things adjust their activity patterns, without any obvious cue, the __2__
time of day, or the month, or the year. They are affected but little,
if at all, by drugs, chemicals, or wide temperature differences—
factors may alter substantially the rates of all ordinary processes of __3__
the body.
The nature of the biological clocks mechanism is still a mystery __4__
two quite different theories have been advanced to account to __5__
them. According to the first of these theories, each individual have
envolved, aided by natural selection, an adaptation to the rhythmic __6__
environment. It has now become independent on the environment __7__
according to this view, the clocks are not perfect timers.
They require regular corrections by the natural light and tide cycles
and the changed lengths of the day throughout the year. __8__
The other theory holds up living things react continuously to __9__
their rhythmic physical environment. The setting of their biological
clocks, therefore, involves a constant adjustment to subtle clocks
which are potential perfect times. __10__