The kidneys make two main hormones, vitamin D and erythropoietin. Vitamin D is essential for a number of different functions in the body. Most of the vitamin D that is in the blood is inactive and it is modified by the kidney and other tissues to activate it.
Is a Mexican film directed, theater and actresses
A Only one variable changed
The substance is called DNA.
Answer:
scientific theories must be tested by more than one individual multiply times for it to become scientific law
