Technically any of these. Are there any other details or specifics. I'd assume participating in sports because a diet only helps stress levels in the long term, watching television can relax a person but the other factors such as lack of social activity can contribute to a person's overall mental state and therefore increase stress levels, and studying can actually be relieving for some people depending on the mental state and needs of them but can obviously be a stresser. The only downfall to participating in sports is getting to excited or emotional during a game for example. But overall, C is the best choice.
Sti stands for Sexually Transmitted Infection. It is referred to sexually transmitted diseases.
Measles<span> virus infection is presumed to be sustained through an unbroken chain of</span>human-to-human transmission. So the term I would use is Human Reservoirs because m<span>any common infectious diseases have human reservoirs. Diseases that are transmitted from person to person without intermediaries . And measles is an example of Human reservoirs. </span>