Which describes a difference between a positive and a negative feedback loop?

A. The output of a system keeps conditions within the body absolutely constant only in a negative feedback loop.
B. The output of a system stimulates another cycle of the system only in a positive feedback loop.
C. The output of a system signals the system to disregard the stimulus only in a negative feedback loop.
D. The output of a system maintains conditions around a set point only in a positive feedback loop.