In one of his experiments with pea plants Mendel observed that when a pure tall pea plant is crossed with a pure dwarf pea plant, in the first generation, `F_1` only tall plants appear.
(a) What happens to the traits of the dwarf plants in this case?
(b) When the `F_1` generation plants were self-fertilised, he observed that in the plants of second generation, `F_2` both tall plants and dwarf plants were present. Why it happened? Explain briefly.

Explanation

(a) The dwarf traits of the plants is not expressed in the presence of the dominant tall trait.
(b) In the `F_2` generation, both the tall and dwarf traits are present in the ratio of 3:1. This showed that the traits for tallness and dwarfness are present in the `F_1` generation, but the dwarfness, being the recessive trait does not express itself in the presence of tallness, the dominant trait.