Which pair of features best characterizes a sound wave?

I know the exact question you're asking, it's a module on edmentum. It's C, hope this helps anyone else too.

dopamine..

"it was found that some people who were taking the drug l-dopa to raise their levels of dopamine were developing schizophrenic-like symptoms supporting research a strength of the dopamine hypothesis is that there are many studies which have shown support for the neurochemical explanation."