Why would the chromosomes carrying the black allele (+) and the tan allele (tn) be considered homologous chromosomes?

The

homologous chromosomes

separate during meiosis I.

This time, the MI results

in two cells, each containing

both genes (1 tan, 1 wild-type); therefore, the genes for spore color have not yet segregated.

Explanation:

Two

homologous chromosomes line up at metaphase I of

meiosis. The two chromatids of one chromosome each

carry the gene for tan spore color (tn) and the two

chromatids of the other chromosome carry the gene

for wild-type spore color (+). The first meiotic

division (MI) results in two cells each containing just

one type of spore color gene (either tan or wild-type).

Therefore, segregation of these genes has occurred

at the first meiotic division (MI). The second meiotic division (MII) results in four cells, each with the

haploid number of chromosomes (lN).

cells spend most of their time in interphase