Question

Arrange the ratios in the order of monohybrid test cross: incomplete dominance; and dihybrid cross.

• A. \( 9:3:3:1 \)
• B. \( 1:2:1 \)
• C. \( 1:1 \)
• D.

Hint:

In genetic crosses, remember that incomplete dominance shows a \( 1:2:1 \) ratio, complete dominance shows a \( 3:1 \) ratio, and a dihybrid cross results in a \( 9:3:3:1 \) ratio.

Answer 1

The Correct Option is B

To arrange the ratios, we need to consider the phenotypic ratios for different types of crosses. Step 1: Incomplete dominance For incomplete dominance, the typical phenotypic ratio is \( 1:2:1 \) as seen in the ratio \( B \). This happens when the heterozygote phenotype is distinct from both homozygous phenotypes. Step 2: Monohybrid cross In a standard monohybrid cross with complete dominance, the phenotypic ratio is \( 3:1 \), which corresponds to \( A \). Step 3: Dihybrid cross In a dihybrid cross, where two genes are involved, the phenotypic ratio is \( 9:3:3:1 \), which corresponds to \( C \). Thus, the correct order is: \[ C - B - A \]