Answer:
"*Because the lymphatic system collects excess tissue fluid, if it were not working, swelling (edema) would occur in the tissues. The thymus cleanses the blood from the cardiovascular system of cellular debris and bacteria."
It is a scientific law
Explanation:
A scientific law states a constant relationship between two or more variables, each of which represents a property or measurement of specific systems. It is a constant and unchanging rule, usually expressed mathematically which allows to predict the unknown based on what is known with logical and real relationships.
A scientific theory is a set of concepts and rules (scientific laws) that express the relationships between observations of such concepts and generates a principle or set of principles to explain a phenomenon.
Animals obtain nitrogen by eating plants which has absorbed nitrogen from the soil.