Question

question 15.
a. mutation in which the dna content of the gene is altered
b. segregation of sister chromatids
c. crossing - over in which alleles are exchanged
d. condensation and segregation of alleles

Explanation:

To solve this, we analyze each option:

• Option A: Mutation altering DNA content isn't shown here (no DNA sequence change, just allele distribution).
• Option B: Segregation of sister chromatids involves separating identical chromatids, but here we see alleles (D and d) which are on homologous chromosomes or after crossing - over? Wait, no—sister chromatids should be identical. But the diagram shows D and d, so maybe not. Wait, no, let's re - evaluate. Wait, the diagram has chromosomes with D and d. Wait, actually, during mitosis or meiosis, sister chromatids segregate. But if we look at the alleles, maybe it's about segregation. Wait, no, crossing - over (Option C) exchanges alleles between homologous chromosomes. But the diagram—wait, the key is: the process shown is the separation of sister chromatids? Wait, no, let's think again. The alleles D and d—if we consider that after DNA replication, sister chromatids have the same allele, but here maybe it's the segregation of sister chromatids (each chromatid has an allele, and they are separating). Wait, no, Option B: Segregation of sister chromatids. Let's check other options:
• Option C: Crossing - over exchanges alleles between homologous chromosomes, but the diagram doesn't show exchange (it shows separation).
• Option D: Condensation and segregation of alleles—condensation is about chromosome condensation, not shown here.

So the correct process is the segregation of sister chromatids (Option B), as sister chromatids (with alleles) are separating.

Answer:

B. Segregation of sister chromatids