Constancy of the chromosome number in successive generations is brought about by the process of

What is the significance of meiosis?

Which of the following statements are correct regarding the importance of meiosis?
$(i)$ It increases the genetic variability in the population of organisms from one generation to the next.
$(ii)$ It decreases genetic variability.
$(iii)$ It occurs in all cells of our body.
$(iv)$ It is an important process for evolution.

Whereas the number of chromosomes is reduced to half in the first meiotic division,what is the need for the second meiotic division?

The significance of meiosis is that it:

Explain the importance of meiosis.