Which process ensures the maintenance of a specific type and a fixed number of chromosomes in organisms across generations?

Which of the following is the significance of $Meiosis$?

The significance of meiosis lies in:

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.

Meiosis is significant because

Which process is essential for maintaining a constant and specific number of chromosomes in organisms across generations?