Question

how do haploid gametes result in diploid offspring?
a diploid egg and a diploid sperm fuse, undergo meiosis once to form a diploid zygote, which grows by mitosis.
a diploid egg and a diploid sperm undergo fertilization to form a diploid zygote that grows through meiosis.
a haploid egg and a haploid sperm fuse to form a diploid zygote that grows by meiosis after fertilization.
a haploid egg and a haploid sperm fuse to form a diploid zygote that grows by mitosis after fertilization.
a diploid sperm fertilizes a diploid egg, and the resulting diploid zygote then grows by mitosis to form an embryo.

Explanation:

Gametes (sperm and egg) are haploid. When they fuse (fertilization), the zygote becomes diploid. Mitosis is the process for growth and development of the zygote into an organism as it produces cells with the same number of chromosomes (diploid). Meiosis reduces chromosome number (not for growth). Diploid gametes are incorrect as gametes are formed by meiosis (haploid). So the correct option is the one with haploid gametes fusing and zygote growing by mitosis.

Answer:

A haploid egg and a haploid sperm fuse to form a diploid zygote that grows by mitosis after fertilization.