Mutations often don't effect the organism because they occur in the recessive gene. That means the dominant gene will cover up the effect of the mutation and it won't be expressed.
Meiosis only occurs in sex cells. It creates four daughter cells. Mitosis can occur in any cell and creates two daughter cells.
Two pros of genetic engineering is that it can select the best traits. It also can prevent bad traits. Two cons of genetic engineering is that it decreases the amount of diversity in organisms. It also may have negative side effects that are unknown.