Scientific law.
A scientific law describes something in nature and predicts how it will behave without explaining.
This is because before a scientific law has been made, numerous observation has been done under different situations. The scientific law is established when a natural event invariable occur given a set of circumstances.
Answer:
Blood, the heart pumps oxygen-poor blood to the lungs to be oxygenated.
Explanation:
:) Merry Christmas!
Proteins are made up of 20 different amino acids