How many pairs of contrasting characters in pea plants were studied by Mendel in his experiments?

Mendel selected and studied seven pairs of contrasting characters in pea plants through his experiments. They are 1. Stem height – tall and dwarf, 2. Position of fl ower – axillary and terminal, 3. Flower colour – violet and white, 4. Seed colour – yellow and green, 5. Seed shape – round and wrinkled, 6. Pod colour – green and yellow and 7. Pod shape – infl ated and constricted.