Why Mendel had choosen garden pea as material for his experiments?

Because it has following advantages.

1. Well defined characters 2. Bisexual flowers
3. Predominently self pollinating, 4. Suitable for cross pollination
5. It is an annual plant.

Mendel hypothesized that characters were carried as traits and an organism always carried a pair of factors for a character. He also hypothesized that distinguishing traits of the same character were present in the population of an organism. He assumed that the traits shown by the pea plants must be in the seeds that produced them. The seeds must have obtained these traits from the parent plants.

How do parent plants pass on their traits to the seeds? Will the seeds from tall plants always produce new tall plants?

Mendel carried out several experiments to find out answers to such type of questions.