Chronic Traumatic Encephalopathy, also known as CTE, is mainly caused by:

• A. Players spending too much time in the sun and heat.
• B. A helmet that fits too tightly.
• C. Concussions from blows to the head.
• D. Bacteria in a player's water bottle.

Answer: (C)

Repeated head impacts over time lead to CTE, a brain condition linked to how often and how hard the head is struck in contact sports. It’s caused by cumulative trauma from multiple hits, not by a single incident. That’s why this option is the best answer. The other ideas don’t fit because sun exposure and heat have no relation to CTE, a helmet that fits tightly isn’t a cause and may even offer protection, and bacteria in a water bottle isn’t connected to brain degeneration. Understanding this emphasizes the importance of limiting repetitive head trauma in athletes.