Answer:
Answer choice A should be correct
Explanation:
B is wrong, your vein size does not increase or decrease depending on whether or not you eat (a lot of, or intermidiate amounts of) protein.
C is not true because the amount of protein doesn't tell you how many red blood cells you have, instead how well they are built (durible, energy eficiant).
D is not true either, protein doesn't nessisarly prevent cancer, the most healthy people in the world can still get cancer
