(a) The possible cross of Mendel’s experiment is:

As a result, tallness (T) is dominant and dwarfness (t) is recessive. Only dominant traits show in the F1 generation; recessive traits are suppressed.
Both dominant and recessive features, or F2 generation, express themselves. Mendel’s experiment demonstrated that the traits (tall and dwarf) are inherited independently in this way.
(b) Mendel compared round/wrinkled seeds and violet/white flowers in his experiment on pea plants in additional to height.