No, it cannot because codominance is the expression of both alleles coming forth from each parent. One parent would be R(A)R(A) and the other parent would be R(B)R(B). Their offspring would only be able to be R(A)R(B). They could not be homozygous.
They don't swell because of osmosis.
I don’t know there’s no picture or anything I need more to answer
The answer is B. Geology has shown a thin layer of iridium (a rare mineral on earth but found on asteroids and meteors) in the rock layers between the Cretaceous and Paleogene periods. Below this layer are numerous fossils of pterosaurs and dinosaurs, but above the layer are drastically few. The aftermath of asteroid impact is believed to have smothered most vegetation from earth which dinosaurs depended on as a source of food.