Anatural state of equilibrium; the body attempts to maintain this equilibrium by constantly reacting to external forces that attempt to disrupt this fine balance:

Homeostasis is the natural state of equilibrium; the body attempts to maintain this equilibrium by constantly reacting to external forces that attempt to disrupt the fine balance. It involves the maintenance of the internal environment constant, this involves conditions such as blood sugar, body temperature, among other factors that enhance functions in the body. Through homeostasis organisms tend to resist changes in order to maintain a stable, and a constant internal environment. 

No because the eaeht is on a 23.5 degree axis tilt and so when it is winter the northern hemisphere is pointing away from the sun and the soutubern hemisphere is pointing toward the sun