what is feedback mechanism and what is negative feddback? please explain briefly

Feedback mechanism may be defined as the process in which some output of the system is returned as input, back to that system in order to maintain the control or performance of that system. There are two types of feedback i.e. positive feedback and negative feedback.

Negative feedback may be defined as the process in which the portion of the output is returned back to the system in order to inhibit the same output by the system. For example the blood glucose level in our body is maintained as a result of a negative feedback. When the level of glucose in our body reaches a certain level, some portion of the glucose is returned back to the organ producing the enzymes involved in its production resulting in a inhibiting effect on its production.