In a simple mendelian monohybrid cross, tall plants are crossed with short plants, and the f1 plants are allowed to self-pollinate. what fraction of the f2 generation are both tall and heterozygous [a] 100% [b] 75% [c] 50% [d] 25% [e] none of the above

The answer is 50%. Mendel found that if true breeding Tall plants are crossed with trues breeding short plants, all the next generation of plants, called F1 generation will all be tall. He also showed that if the F1 plants are self pollinated they produce an F2 generation with 3/4 of the plants tall and 1/4 short. Among the 3/4 plants that are tall, 1/4 is homozygous (TT) and 1/2 is heterozygous (Tt)