In humans, at the end of the first meiotic division, the male germ cells differentiate into the:

Explanation

Note: During embryonic development the primordial germ cells migrate to the testis where they become spermatogonia. At puberty the spermatogonia proliferate rapidly by mitosis. Some undergo growth phase to become primary spermatocytes that further undergo through meiotic division I to become secondary spermatocytes. After completion of meiotic division II the secondary spermatocytes produce spermatids which differentiate to form spermatozoa. The correct option is: d) Secondary spermatocytes. Explanation of each option: a) Spermatids: Spermatids are the result of the second meiotic division of male germ cells. After the first meiotic division, primary spermatocytes are formed. These primary spermatocytes then undergo the second meiotic division to produce haploid spermatids. Spermatids are the immediate precursors of spermatozoa (sperms) and further undergo spermiogenesis, a process of cellular differentiation and morphological changes, to develop into mature sperm cells. b) Spermatogonia: Spermatogonia are the undifferentiated diploid stem cells that reside in the seminiferous tubules of the testes. They are the "germ cells" that continually divide by mitosis to replenish the pool of germ cells and provide a continuous supply of cells for spermatogenesis. Spermatogonia differentiate into primary spermatocytes when they enter meiosis. c) Primary spermatocytes: Primary spermatocytes are formed when spermatogonia enter meiosis (the process of gamete formation involving two rounds of cell division). These primary spermatocytes are diploid cells, meaning they contain the full complement of chromosomes (46 chromosomes in humans). They undergo the first meiotic division to form secondary spermatocytes. d) Secondary spermatocytes: This is the correct option. At the end of the first meiotic division, primary spermatocytes divide into secondary spermatocytes. This division is a reductional division, meaning the number of chromosomes is reduced by half. Secondary spermatocytes are haploid cells with 23 chromosomes each in humans. After this division, secondary spermatocytes will undergo the second meiotic division to form spermatids, which will eventually mature into spermatozoa (sperms). In summary, option (d) Secondary spermatocytes is the correct answer. At the end of the first meiotic division, male germ cells differentiate into secondary spermatocytes, which are haploid cells with 23 chromosomes. The process of meiosis is essential for the generation of haploid sperm cells from diploid spermatogonia.