There is 20 chromosomes in a adult wild mouse
Here is a good resource:
https://nhlbi.nih.gov/health/educational/lose_wt/eat/calories.htm
I attached the image related to your concerned question.
In theory, the part of the brain that is responsible for the sleep wake cycle is the hypothalamus; specifically, the ventrolateral preoptic nucleus of the hypothalamus. In the image, the location of the hypothalamus is pointed by the green square.
Reduction is to bring down the size or value of intensity of a certain thing. Decrease is to decrease or “bring down” of a quantity or to become smaller.
Pain is one example of a sensation