B because the temperature goes up then the birds would move to the south were it is cooler.
My answer is the Vacoules, but I might be wrong.
Hypothalamus is a part of the brain that links the nervous system to the endocrine system via the pituitary gland. It helps maintain the internal environment constant by regulating major processes in the body such as the heart rate and the body temperature. It is therefore, both a neural and endocrine organ.
