Which process maintains the stability of the chromosome number in the generation produced by sexual reproduction?

The significance of meiosis is that it:

$A$: Meiosis is an important process for evolution. $R$: Crossing over induces genetic variation in a species.

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.

The significance of meiosis lies in:

What is the significance of meiosis?