What is the main difference between diploid and haploid cells?

The correct answer highlights an essential aspect of cellular biology: the number of chromosome sets in diploid versus haploid cells. Diploid cells contain two complete sets of chromosomes, one set inherited from each parent, which is represented as 2n. In contrast, haploid cells have only one complete set of chromosomes (n), typical of gametes like sperm and eggs in organisms that reproduce sexually.

This distinction is crucial because it plays a significant role in sexual reproduction, genetic diversity, and the passing of genetic information to offspring. During fertilization, two haploid gametes combine to form a diploid zygote, restoring the diploid number of chromosomes necessary for normal development in the organism.

Understanding this difference is fundamental to genetics and developmental biology, as it underpins how organisms maintain their chromosome numbers from generation to generation and how they ensure genetic variation through sexual reproduction.