Part of Gregor Mendel's hypotheses of inheritance proposed that when two contrasting traits occur together, one them may be completely expressed, while the other may have no observable effect on the organisms appearance. He called the expressed trait dominant and the unexpressed trait recessive. In his genetic experiments, mendel studied seven contrasting traits of peas. One of the traits he studied was the trait for seed shape--wrinkled and round. In an experiment to determine which form of this trait was dominant, Mendel performed the following experiment