Most plants have roots, but there are some
exceptions. The exceptions are bryophytes
and the groups of green algae that are
classified as plants. Bryophytes have rootlike
structures called rhizoids for absorbing
water, but because rhizoids lack vascular
tissue they are not considered roots.
Hallo~~
Your question is related to genetics.
Have you ever done a Punnett Square? This question forces you to make one. If your cross a homozygous type A (AA) and homozygous type O (OO) you should get 100% AO. Understanding genetics, an AO gene means a type A blood. Therefore, it's 100% type A blood (AO).
I attached a picture showing how to do it
