Both plant and animal cells have membranes so whatever chemical reactions they have going inside the cell, it is regulated and maintained. Membranes help separate the internal environment from the external environment.
Hope this helps - I'm currently in cell biology so this question is interesting
Answer: The Pulmonary Arteries
Explanation: They are two pulmonary arteries with on serving each human lungs, which brings deoxygenated blood to the lungs from the hilium. The arteries go into the capillaries of the alveoli. Capillaries are the thinnest ,smallest blood vessel,they supply oxygen to single tissues in all parts of the human body.