The field mouse has 40 chromosomes. How many chromosomes does a male mouse have in spermatogonia, from which sperm formation begins, in mature spermatozoa and in embryonic cells? What division leads to the formation of these cells? What cells do they form from?
1) Spermatogonia is formed by mitosis, in them 40 chromosomes.
2) Sperm cells are formed from spermatogonia by dividing meiosis, each containing 20 chromosomes.
3) Embryonic cells are formed by dividing the zygote (a fertilized egg) by mitosis, each containing 40 chromosomes.
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