Question

An individual produced during a cross between two pure plants differing in two pairs of contrasting characters is always _________

• A. homozygous for the two selected traits
• B. heterozygous for the two selected traits
• C. heterozygous for none of the traits
• D. homozygous for one trait and heterozygous for other trait

Hint:

In any cross between two pure lines, the F\textsubscript{1} generation is always heterozygous for the contrasting traits.

Answer 1

The Correct Option is B

Step 1: Understanding the cross.
A cross between two pure plants differing in two pairs of contrasting characters is known as a dihybrid cross. The parent plants are homozygous for both traits, for example, AABB and aabb.

Step 2: Formation of F\textsubscript{1 generation. When these two pure lines are crossed, each parent contributes one allele for each trait. As a result, all F\textsubscript{1} individuals receive one dominant and one recessive allele for both traits, forming the genotype AaBb.

Step 3: Nature of F\textsubscript{1 individuals. Since each trait in the F\textsubscript{1} generation has dissimilar alleles, the individuals are heterozygous for both selected traits.

Step 4: Conclusion.
Therefore, an individual produced in such a cross is always heterozygous for the two selected traits.