What are homologous chromosomes?
a. chromosomes that are similar in their size, shape, and gene content.
b. any chromosome in a diploid cell.
c. the two chromatids in a replicated chromosome.
d. similar chromosomes that are found in different individuals of the same species.

The correct answer is a. chromosomes that are similar in their size, shape, and gene content.

Explanation:

A homologous chromosome is the chromosome which is similar in shape, size, centromere position and they contain the same genes at the same locus also.  

One homologous chromosome comes from the father and the other homologous chromosomes come from the mother. These chromosomes have the same gene at the same locus but the alleles of that gene can be different in homologous chromosomes.  

The homologous chromosome separates during the meiosis so that the gamete has half the number of chromosomes. So the correct answer is a.

b is the best answer for this question.

as in mitosis, dna replication occurs during interphase.   in meiosis, it occurs specifically in s phase of interphase 1.