a subatomic particle of about the same mass as a proton but without an electric charge, present in all atomic nuclei except those of ordinary hydrogen.
Answer:
The exchange of biological material between tissues and blood vessels.
Explanation:
Capillaries are extensions of blood vessels but are much thinner in diameter. They are mostly found in tissue that is highly metabolic like the kidneys and liver which require high perfusion and exchange rate of metabolic molecules between tissue and blood.
If a hypothesis is supported consistently by different observations or experiments, it may be advanced to the level of a(n) <u>theory</u>.
