Answer:
Homologous chromosomes contain the same gene loci but may have different alleles of a particular gene. Sister chromatids are identical copies of each other produced during DNA replication.
Explanation:
Homologous chromosomes can be described as the chromosomes which are identical to one another and carry the same genes. The position of a gene on the chromosome is called as loci. The homologous chromosomes carry the same genes but the alleles for these genes might be similar or might not be similar. The allele which masks the effect of another allele is termed as the dominant one.
Sister chromatids are however identical copies of each other carrying the same alleles. They are exactly duplicate of one another.