Which of the following contributes ammonia to soil in the nitrogen cycle ? OA. atmospheric nitrogen
ОВ.
dissolved nitrogen in rain
OC. urine and dead plants and animals
OD.
all of these

The circles, or orbits, for electrons are called energy levels. each level can hold only a certain number of electrons. add electrons to each level until you can't add any more. how many electrons can each level hold?

Which group of molecules are targeted by the kinases in order to control this movement

Asquirrel population lives in an area. over many years, a river in that area grows wider and stronger, eventually forming a canyon. the squirrel populations on the two sides of the canyon can no longer mate with each other and ultimately form distinct species. this is an example of