Definition of the science of building

In what for do plants utilize nitrogen? why do they need nitrogen?

What is the next step in muscle contraction after the actin changes shape? (apex)

Cattle with brown fur and cattle with white fur will produce a reddish roan calf . when examined closely, the calf show about an even number of brown hairs and white hairs that give a reddish appearance when viewed from far away. the fact that both the brown fur allele and the white fur allele are expressed equally in the offspring is an example of