Which of the following statements are true of feedback mechanisms? (Read carefully and select all of the correct statements.)

A)A feedback mechanism is called positive if it has a good effect within the body.
B)A feedback mechanism is called negative if it has the potential to become a vicious cycle.
C)A positive feedback mechanism contains its own brake.
D)A negative feedback mechanism requires an external brake.
E)For the secretion of hormones, positive feedback mechanisms are more common than negative ones because they work faster.
F)In stressful situations, positive feedback mechanisms become negative ones.
G)None are correct.