The answer is (1) A brain injury that can change the way your brain works, (2) Potential long-lasting brain damage, and (4) A serious brain injury usually caused by a blow to the head or body.
Explanation:
A concussion is a type of traumatic brain injury—or TBI—caused by a bump, blow, or jolt to the head or by a hit to the body that causes the head and brain to move rapidly back and forth. This sudden movement can cause the brain to bounce around or twist in the skull, creating chemical changes in the brain and sometimes stretching and damaging brain cells. The symptoms of a concussion are usually temporary but can include headaches and problems with concentration, memory, balance and coordination.
