At what age does your body start increasing the size of existing fat cells?

During infancy and adolescence, adipose tissue is growing by a combination of the increase in fat cell size (to a lesser extent) and (above all) the number of these cells. In adults, fat cell number is constant over time in spite of a large turnover (about 10% of the fat cells per year) when body weight is stable.

fluid balance is an aspect of the homeostasis of organisms in which the amount of water in the organism needs to be controlled, via osmoregulation and behavior, such that the concentrations of electrolytes (salts in solution) in the various body fluids are kept within healthy ranges. the core principle of fluid balance is that the amount of water lost from the body must equal the amount of water taken in.

because health skills are tools and strategies and also practical skills are also something you need to learn (like tools and strategies) and put it in reality.