You are studying two traits in fruit flies:

Eye color where there are two colors, brown and red, and wing shape where there are straight and curled phenotypes.
You mate two flies that are heterozygous for the genes that control both of these traits and get the following phenotypes in the following ratio:
9 red and straight; 3 red and curled; 3 brown and straight; 1 brown and curled.
Considering these traits, which alleles separated at which stages of meiosis?

a. red segregated from brown in meiosis I, and straight segregated from curled in meiosis II
b. red segregated from brown in meiosis II, and straight segregated from curled in meiosis I
c. red segregated from brown in meiosis I, and straight segregated from curled in meiosis I
d. red segregated from brown in meiosis II, and straight segregated from curled in meiosis II
e. red segregated from straight in meiosis I, and brown segregated from curled in meiosis II

This is a typical dihybrid cross involving two genes; one coding for eye color and the other for seed shape. According to Mendel, for each trait, an organism (fruitfly in this case) receives two forms of a gene called ALLELE, from each parent. These two alleles get separated into gametes in an equal frequency during meiosis.

In this case of heterozygous parents i.e. they have a combination of the variant genes (alleles) that controls both traits, each parent has a brown and red allele for one gene and a straight and curled allele for the other gene. These two alleles for each gene were each received from the male and female parent.

In meiosis I, homologous chromosomes (similar but non-identical chromosomes received from each parent) separate. Hence, each allele of all the genes separates into gametes. Both red and brown allele separates into different gametes, while straight and curled alleles also separate into different gametes. This happens in a way that each gamete must contain one allele of each gene. Both occurs in meiosis I because the alleles for the different traits are borne on homologous chromosomes, which separate in the Anaphase stage of meiosis I.