Final answer:
In sexual reproduction, diploid organisms produce haploid gametes, which unite during fertilization to form a diploid zygote. The zygote then undergoes meiosis to produce more haploid gametes.
Step-by-step explanation:
In sexual reproduction, a diploid organism produces haploid gametes.
These gametes contain half the number of chromosomes as body cells, allowing for the formation of a diploid zygote when they unite during fertilization.
The diploid zygote then undergoes meiosis to produce more haploid gametes, repeating the life cycle.