Final answer:
Adequate sleep is crucial for the healing process after a concussion because sleep aids in cognitive and physical recovery, including brain restoration.
Step-by-step explanation:
The statement about sleep that is true when recovering from a concussion is that adequate rest is crucial for the healing process. Since sleep is essential for restoration and recovery, it is predicted that the more active an individual is, the greater their total sleep duration would be to compensate for the increased physical demand and aid in recovery. During sleep, particularly during the REM (rapid eye movement) and deep sleep stages (stage 3), important processes related to cognitive and physical recovery occur. Hence, when recovering from a concussion, which is a type of mild brain injury, ensuring to get optimal sleep can help the brain to heal and rejuvenate more effectively.