Answer:b
Explanation:I am not positive but I think that’s it
The answer is photosynthesis.
<span>Photosynthesis
occurs in the leaves of green plants. During photosynthesis, carbon
dioxide and water are converted into using the energy of
sunlight to glucose and oxygen. After great evolution of plants, the photosynthetic rate was increased. More plants mean more oxygen produced in the process of photosynthesis. Thus, photosynthesis </span><span> is most responsible for the increase in early Earth’s atmospheric oxygen levels.</span>
An energy resource that can be replaced by nature in a relatively short time is known as a "<span>inexhaustible energy resource" but these are very rare in nature. </span>
During the S phase in the cell cycle, the chromosomes are replicated so that there are two copies. These copies are necessary so that each daughter cell created during the M phase will have an identical copy of the DNA.
Therefore, the answer is A: The DNA must be replicated.
The chromosomes joining, cell membrane expanding, and cytoplasm separating all happen during the M phase (mitosis).