Which of the following is not true of Mendel's experiment?

A. Mendel crossed two true-breeding plants.

B. The yellow trait seemed to disappear in the first cross.

C. The yellow trait reappeared in the second cross.

D. Mendel proposed that the green pods were recessive.

The correct answer is option (D) Mendel proposed that the green pods were recessive.

Gregor Mendel discovered the principles of heredity with his experiments on garden pea plant. He crossed two true - breeding characters like tall and dwarf, round and wrinkled seeds, axial and terminal flowers and green pod and yellow pods of the seeds.

When he crossed the pea plants having domiant green pod (GG) with recessive yellow pod (gg). The gametes G and g produced an F 1 generation hybrid Gg which was green in colour. The yellow trait had disappeared. In the F 2 generation obtained by crossing Green (Gg) plants produced, three green plants and one yellow plant showing the reappearance of the yellow trait.

Thus, mendel crossed two true-breeding plants of pod colour, the dominant green and the recessive yellow, showing the disappearence and reappearence of the yellow trait in the first and second generation respectively.