The body already produces enough protein to get by just fine. However, many people think athletes "use up" too much protein and faster than they gain it back, but that is not true because the body regulates homeostasis. I hope I helped :)
According to these criteria, the service sector covered in this paper is the economic activities other than agriculture, hunting, forestry and fishing, mining and quarrying, manufacturing, utilities (electricity, gas and water supply) and construction
You didn't provide a graph? Generally, when we're talking about homeostatis, we're talking about the neutral state of the body during which it can function optimally. If you've provided a graph which involves the human body under an intense workload, then we can be sure that during this period the body isn't under homeostasis.