A sugar, a phosphate group, and a nitrogen base
Because the different environments permit some organisms to thrive, while others cannot. ... Similarly, a fish (extremely suited to its aquatic environment) can't survive out of water. A characteristic which allows growth in one environment will not necessarily allow growth in another.
The brain's suprachiasmatic nucleus regulates the body's circadian rhythms. The suprachiasmatic nucleus is a minute region of the brain located in the hypothalamus above the optic chiasm, the circadian rhythm is the 24-hour cycle of organisms, related to sunlight and temperature.