Final answer:
Gametes unite, forming zygotes with two sets of chromosomes. Each gamete contributes one set of chromosomes, and when they combine, the resulting zygote has two sets of chromosomes, one set from each parent. When gametes unite, they form a zygote, which is a diploid cell with two sets of chromosomes.
Step-by-step explanation:
In sexual reproduction, gametes are haploid cells with one set of chromosomes. When gametes unite, they form a zygote, which is a diploid cell with two sets of chromosomes. Each gamete contributes one set of chromosomes, and when they combine, the resulting zygote has two sets of chromosomes, one set from each parent. So, the answer is Gametes unite, forming zygotes with two sets of chromosomes.
During sexual reproduction, specialized reproductive cells called gametes (sperm and egg) unite during fertilization, forming a zygote. Each gamete contributes one set of chromosomes, and when they combine, the resulting zygote has two sets of chromosomes, one set from each parent. When gametes unite, they form a zygote, which is a diploid cell with two sets of chromosomes. This process restores the diploid number of chromosomes in the zygote, which will eventually develop into a new organism.