Answer:
D. ususally very abundant in an ecosystem
Explanation:
Most commercial phosphorus is produced by mining and heating calcium phosphate. Phosphorus is the eleventh most abundant element in the Earth's crust
It is always beneficial to study the diseases of other animals because many of these diseases can be transmitted to humans as well. It's also essential in order to save the lives of dogs.
The coefficient for Fe will be 6, because the left side Fr equals 6.