What is the primary function of haploid cells in sexual reproduction?

The primary function of haploid cells in sexual reproduction is to form diploid zygotes when they combine during fertilization. Haploid cells, which carry one set of chromosomes, are produced through meiosis. In sexual reproduction, two haploid gametes (one from each parent) merge to create a diploid zygote containing two sets of chromosomes, one from each parent. This zygote undergoes further development to eventually form a new organism, maintaining the genetic diversity that is crucial in sexual reproduction.

The other answer choices do not align with the primary role of haploid cells. While energy production and cellular respiration are critical processes for any living organism, they are not the key function of haploid cells during reproduction. Moreover, the transport of nutrients is an essential function within multicellular organisms, but it does not relate to the role of haploid cells in sexual reproduction.