Which of the following statements is true regarding sexual reproduction in organisms?

Sexual reproduction needs two parents. Each parent produces sex cells called gametes (sperm and egg in animals, pollen and ovule in plants) by meiosis, so each gamete carries half the normal number of chromosomes. When a male gamete fuses with a female gamete at fertilisation, a zygote is formed with the full chromosome number restored.

Because the offspring gets a mix of genes from both parents, and because crossing over and random assortment happen during meiosis, the offspring is genetically different from both parents and from its siblings. This is genetic variation, and it helps a species adapt and survive changes in the environment.

The other statements describe asexual reproduction, where one parent produces offspring by mitosis with no gametes and no fertilisation, giving clones that are genetically identical to the parent. So the true statement about sexual reproduction is that it involves the fusion of gametes from two parents and gives offspring with genetic variation.