What process takes place in meiosis but not in mitosis

In the process of mitosis, the daughter cells produced are similar, while in meiosis, the daughter cells produced are distinct due to the process of crossing over taking place. The incidents or phenomenons that takes place in meiosis but not in mitosis comprise crossing over, pairing up of homologous chromosomes, and lining up along the metaphase plate in tetrads.  

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

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what's the question ?