Ok so with this question, I knew that NO is a relaxer since the passage says and that L-NMMA is an inhibitor of NO synthase. However, when going through the answer choices, I did not want to make the direct assumption that the absence of NO due to L-NMMA directly leads to constriction of the blood vessels. Therefore if NO isn't present; this would allow acetylcholine to affect the blood vessel without having to compete with NO. I don't know, I just feel like they are a lot of questions on...
SPOILER AAMC Qbank Bio Vol 1, #55
SPOILER AAMC Qbank Bio Vol 1, #55