How many meiotic divisions are required to produce $28$ cells from a single cell?

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

$A$: In higher organisms,a constant number of chromosomes is maintained generation after generation.
$R$: Meiosis occurs during the formation of gametes in plants and animals.

Meiosis is significant because

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 is that it-