Final answer:
Meiosis contributes to genetic diversity in sexually reproducing organisms by producing four unique haploid cells, thereby increasing variation in a population.
Step-by-step explanation:
Meiosis is the type of cell division that produces gametes, leading to genetic variation in sexually reproducing organisms. During this process, crossing-over during prophase I, random assortment of chromosomes during metaphase I, and the random union of gametes from different parents all contribute to this variation.
Unlike mitosis, which produces genetically identical cells, meiosis results in four haploid cells that are genetically unique. Therefore, the correct answer to why meiosis causes offspring to be genetically diverse is that it produces genetically unique cells that will increase variation in a population.