Speeding up or slowing down, Speaking aggressively , Checking your inflection , Talking more loudly or quietly
Phagocytosis which is the devourment of foreign particles.
Dangerous conditions influencing sport injuries include all answers which you've mentioned (overuse, overexertion, and incorrect technique). It doesn't, however, include practicing and drills - d.
Practicing and drills is the thing which would help us become more profficient at a certain task and eventually sport through it.
Answer:
Fear (from a quick Google search): "An unpleasant feeling triggered by the perception of danger, real or imagined."
Simply put, fear keeps us safe (or at least tries to). It helps keep us on the lookout for things that could be of harm to us.