'Gregor Mendel in examining tea plants found two Sharply marked races - the tall and the short - he experimentally fertilized flowers of tall plant with pollen of Short. The off spring were tall plants. He next let the flowers of this first generation be fertilized with their own pollen. In the following generation - shortness reappeared. Tallness and shortness were distributed not at random but in a definite - constant - and simple ratio: three dominant talls to one recessive short' Which one of the following aptly describes the distribution of dominant and recessive characteristics?