The number of chromosomes in parents and offsprings of a particular species remains constant due to:

1. doubling of chromosomes after zygote formation.
2. halving of chromosomes during gamete formation.
3. doubling of chromosomes after gamete formation.
4. halving of chromosomes after gamete formation.

Correct Answer: (b) halving of chromosomes during gamete formation

Explanation:

 The number of chromosomes in parents and offsprings of a particular species remains constant due to the halving of chromosomes under the meiosis process during gamete formation.

Meiosis is a reductional division process where a single cell divides two times to form four cells containing half the amount of genetic material present in the mother cell.