When Mendel crossed a strain of tall pea plants with a strain of short pea plants he observed that all of the plants in the F1 generation were tall. This suggests that?

This suggests that the trait for tallness is dominant over the trait for shortness in pea plants. Since all the F1 generation plants exhibited the tall phenotype, it indicates that the allele for tallness masks the expression of the allele for shortness when both are present. Mendel's experiments demonstrated the principles of dominance and inheritance, laying the foundation for modern genetics.