Which substance is a waste that would normally diffuse across the placenta from the embryo to the mother?

What do science, technology, and disease have to do with each other?

In a cross between individuals of a species of tropical fish, all of the male offspring have long tail fins, and none of the females possess the trait. mating two of the f1 fish fails to produce females with the trait. explain the inheritance pattern of the trait.

What is the similarities and differences between bacteria and eukaryote?