Question

what is the result of a rise in body temperature​

Answer 1

If our body temperature rises (more than 36-37 degree Celsius), then we suffer from fever because increased temperature denatures the body's hormones and enzymes leading to an imbalance in the body resulting in fever.

The similar is the case if the temperature is low. When the temperature is low, the body's enzymes and hormones get deactivated. This too results in fever.

Hence, a proper body temperature is maintained in mammals and aves.