The type of cell division responsible for gamete formation and sexual reproduction is meiosis.
Meiosis is a specialized form of cell division that reduces the chromosome number by half, creating four haploid cells from a single diploid cell. This process is crucial for sexual reproduction as it produces gametes, which are the sperm and egg cells in animals. During meiosis, each gamete contains a unique combination of genes due to the processes of crossing over and independent assortment, contributing to genetic diversity in offspring.
In contrast, mitosis is the type of cell division used for growth and repair, resulting in two identical diploid daughter cells. Unlike meiosis, mitosis does not alter the chromosome number and does not contribute to genetic variation.