During spermatogenesis, __X___ undergo first meiotic division and results in ___Y____. 

X and Y are

Spermatogenesis is the process by which male germ cells, called spermatogonia, develop into mature sperm cells, known as spermatozoa. 

• Spermatogonia: Spermatogenesis begins with spermatogonia, which are diploid (2n) stem cells located in the seminiferous tubules of the testes. These spermatogonia undergo mitotic divisions to produce more spermatogonia and also give rise to primary spermatocytes.
• Primary Spermatocytes (X): Primary spermatocytes are the first stage of meiotic division in spermatogenesis. They are diploid cells (2n) and are formed from spermatogonia. During the first meiotic division (meiosis I), each primary spermatocyte undergoes DNA replication, resulting in two haploid (n) daughter cells called secondary spermatocytes.
• Secondary Spermatocytes (Y): Secondary spermatocytes are the immediate product of the first meiotic division of primary spermatocytes. They are haploid (n) cells and contain half the chromosome number of the original primary spermatocytes. These secondary spermatocytes are now ready to undergo the second meiotic division (meiosis II).
• Spermatids: After the second meiotic division (meiosis II), each secondary spermatocyte divides into two haploid spermatids. Spermatids are round cells with half the chromosome number of the original primary spermatocytes. They are not yet fully mature sperm.
• Spermatozoa: Spermatids then undergo a process called spermiogenesis, during which they undergo structural changes and differentiate into mature spermatozoa or sperm cells. This process involves the development of the characteristic tail (flagellum) and the loss of excess cytoplasm.