Josef has had a very demanding day. Though his work is not physically challenging, it tends to mentally drain him. Which type of sleep will Josef probably require more of?

Rapid Eye Movement sleep (REM sleep)

Explanation:

Rapid Eye Movement sleep (REM sleep) is the phase of sleep that occurs in about 90mins after one falls asleep, and involves the rapid movement of the eyes in its sockets, with increase in heart rate and irregular breathing as mixed frequency of brain activity occurs. Most of our dreaming occurs during REM sleep, while the body is at rest. REM sleep is said to increase brain activity as well as promote learning. REM sleep improves and consolidates memory.