Which of the following cells in spermatogenesis is diploid?
primary spermatocyte
secondary spermatocyte
spermatid
sperm

primary spermatocyte

Explanation:

The primary spermatocyte is a diploid cell (2n). This cell undergoes a reducing division or first meiotic division, forming two secondary spermatocytes, which are haploid (n) and approximately half the size of the parent cell. As in all meiosis, two successive divisions occur, the secondary spermatocytes undergo another meiosis, forming four haploid cells, the spermatids, which are half the size of the mother cells.