Which order of events is correct?

mitosis -> cell differentiation -> stem cells

Explanation:

Zygote Definition: a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum.

Mitosis: a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth.

Cell Differentiation Definition: Cellular differentiation, or simply cell differentiation, is the process through which a cell undergoes changes in gene expression to become a more specific type of cell.

Stem Cell Definition: an undifferentiated cell of a multicellular organism which is capable of giving rise to indefinitely more cells of the same type, and from which certain other kinds of cell arise by differentiation.

Since cell differentiation can not come before mitosis so the 2nd option is wrong. Stem cells can not turn into zygote cell option 1 is wrong. Cell differentiation would come before stem cells since stem cells are a final product, the 4th option is wrong. So I think option 3 is correct.

did you fail the test? xd

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.