During spermatogenesis which if the following undergoes meiosis 2 to produce four haploid mature sperm cells

The primordial germ cell in the embryo undergoes mitosis to produce a spermatogonial stem cell. 

The spermatogonial stem cell undergoes mitosis. The new cells could either be stem cells or spermatogonium cells. 

The spermatogonium undergoes mitosis to generate a primary spermatocyte. 

*** Up until this point, all cells are diploid  

The primary spermatocyte (diploid) undergoes MEIOSIS I to generate TWO haploid secondary spermatocytes. 

Each secondary spermatocyte undergoes MEIOSIS II to generate a total of FOUR early spermatid. 

The spermatid mature in the seminiferous tubule, and once they are completely mature they are released into the lumen. 

Now called sperm cells, they pass into the epididymis, where they are stored until time to be released during ejaculation.

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Answer: the dna polymerase checks for errors in dna to prevent replication mistakes.
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