Question

a man with blood group A marries a woman with blood group O and their daughter has blood group O is this information enough to tell you which of the trait blood group A or O is dominant? why or why not?

Answer 1

Of course its not enough.
No Because we are not clear about the alleles.

Answer 2

•O is dominant trait.

• because the dominant trait suppress the recessive trait.

• O suppress the A. so,O is dominant trait and A is recessive trait.