What is the best way to keep your brain alert amd focused?

STAY ALERT. To stay alert during the day, it is very important to get enough hours of sleep, a teenager should sleep not less than 9 hrs, an adult person should sleep at least 6-7 hrs, when you sleep the required hours which are needed for your brain to get rested, you will wake up refreshed and able to start your day alert and able to focus and pay attention.