Answer:
If the checkpoint mechanisms detect problems with the DNA, the cell cycle is halted, and the cell attempts to either complete DNA replication or repair the damaged DNA. If the damage is irreparable, the cell may undergo apoptosis, or programmed cell death 2.
Why is there less genetic variation among humans than among other species? this statement is debatible
Explanation:
In regard to the options, species may exhibit less variation when their branches represent the youngest lineages, suffer loss of genetic variation during evolution (i.e., genetic bottleneck) or show low mutation rates
When half of the earth is facing the sun we have daylight.
<u>Explanation:</u>
The earth rotates about its in every 24 hours. When the earth's one of the sides faces the sun, then days occurs. When the side of the earth is far away from the sun, then night occurs. The earth rotates in an anticlockwise direction when we view form the north pole. The daylight sweeps the darkness from east direction to that of the west across the world.
All planes have day and night times because they all rotate about their axis. The day and night cycle time or the length differs for each planet. this is because the speed in which they rotate differs. The planet mars has the same day and night cycle length as earth.
I think the most accepted Theory to make up living things is the cell theory.