Answer:
Haploid cells have only one set of chromosomes due to meosis.
Step-by-step explanation:
Gametes are sex cells.
Gametes contain half the chromosomes contained in a normal diploid cell.
Gametes are produced as a result of meiosis.
During meiosis, the chromosome number is reduced to half and each daughter cell receives half the set of chromosomes.
These gametes unite together to form a zygote.
If both the gametes were diploid, the zygote will have double the number of chromosomes of somatic cells, which in turn results in an abnormal organism.
Thus, gametes have a haploid number of chromosomes.