Do you think oxygen turns the penny dark brown all the way through or just on the surface

C). low

This depends on the neurotransmitter deficiency. neurotransmitters are often decreased or imbalanced in the setting of mental health or psychiatric disorders as well as various neurologic disorders. for instance, the deficiency of the neurotransmitter dopamine is one of the main etiologic causes of parkinson's disease; the deficiency of the most abundant neurotransmitter acetylcholine will lead to body weakness similar to myasthenia gravis or lambert-eaton syndrome. in conclusion, the affectation of low levels of neurotransmitters depends on the neurotransmitter involved.

  i'm actually taking a test and, the same question happened to show up!   i know this is your question. however, i figured since this was 6 days ago..maybe you have the answer now? let me know! : ))- sara perez