How many contrasting traits of pea pod were chosen by Mendel?
A. 7
B. 2
C. 4
D. 3

Hint: To deduce an answer, we must first understand why Mendel carried out these experiments. They were solely carried out to study the processes of genetic variation. Try to understand the term genetic variation and you can then possibly derive an answer.

Complete answer:
Mendel used the pea plant scientifically known as Pisum sativum to study the process of genetic variation. Genetic variation is defined as the difference in DNA in different individuals or the difference between populations.
For his experiments, Mendel studied contrasting characters such as Seed shape, Seed color, Flower color, Flower position, Pod shape, Pod color, and Stem height.
When Mendel considered the pea pod, he chose two pairs of contrasting characters. The two contrasting characters are mainly pod shape and pod color respectively. The dominant trait in pod shape is full however in the recessive form it is constricted. However, in the case of pod color, the dominant trait is green and the recessive trait is yellow.

Thus the correct option is (B) 2.

Note: The various experiments carried out by Mendel lead to the postulation of the three most important doctrines of genetics which are mainly the law of dominance, law of independent assortment, and the law of segregation. It took Mendel exactly eight years to carry out his experiments with pea plants during which he grew about ten thousand plants. Mendel's words were not understood and appreciated during that time. It was however in 1900 that his laws were discovered again and gained widespread appreciation.