In mendel's experiments with pea plants, he observed that when true-breeding tall plants (tt) were crossed with true-breeding short plants (tt), all of the offspring were tall. which of the following statements best explains this result?
a) tallness is a dominant trait, and shortness is a recessive trait.
b) tallness is a recessive trait, and shortness is a dominant trait.
c) tallness and shortness are codominant traits.
d) tallness and shortness are incompletely dominant traits.