Question

1. * 7 points 2017 - q39 39 which diagram demonstrates how crossing - over contributes to genetic variety during meiosis? a b c d a b c d 7 points

Explanation:

• Option A: This is a Punnett square, which is used to predict the genotypes of offspring from a genetic cross. It does not show crossing - over.
• Option B: This diagram shows chromosomes lined up at the equator of the cell during cell division (possibly metaphase). It does not illustrate crossing - over.
• Option C: This diagram shows homologous chromosomes (with genes labeled, e.g., \(R/r\) and \(T/t\)) undergoing crossing - over. Segments of non - sister chromatids are exchanged, which contributes to genetic variety as new combinations of alleles are formed.
• Option D: This diagram shows DNA replication (semi - conservative replication where new strands are formed from old strands), not crossing - over.

Answer:

C.