Imagine a Hypothetical Pathway in Which Precursor X and Precursor

Multiple Choice

Imagine a hypothetical pathway in which precursor X and precursor Y are combined by enzyme Z in order to produce neurotransmitter XYZ. You observe that as levels of XYZ increase in the cytoplasm, the activity of enzyme Z slows down. This is an example of

A) positive feedback.
B) feedback inhibition.
C) retrograde transport.
D) anterograde synthesis.
E) a rate limiting step.