The system that is made up of those is called the Respiratory System
The endocrine system or the skin (:
The second one probably because of the law of conservation of mass where mass is not created or destroyed, so the mass has to be the same.
Answer:
Capillaries connect the arteries to the veins. The arteries deliver oxygen rich blood to the capillaries, where the exchange for oxygen and carbon dioxide occurs.
Explanation:
Hope this helps!