Question

a scientist observes a pair of separate chromosomes that have genes for the same trait arranged in the same order. however, some of the alleles for the genes are different. what is the scientist most likely observing?

• homologous chromosomes with heterozygous alleles
• homologous chromosomes with homozygous alleles
• heterozygous chromosomes with heterozygous alleles
• heterozygous chromosomes with homozygous alleles

Explanation:

1. Recall the definition of homologous chromosomes: they are pairs of chromosomes (one from each parent) with genes for the same traits in the same order.
2. Heterozygous alleles mean the two alleles for a gene are different, while homozygous alleles are the same.
3. The observed chromosomes have the same gene order (so homologous) and different alleles (heterozygous). The other options are incorrect: "heterozygous chromosomes" is not a standard term, and homozygous alleles would mean identical alleles (contradicting "some alleles different").

Answer:

A. homologous chromosomes with heterozygous alleles