For decades, sleep was treated by medical researchers primarily as a period of rest. More recent neuroscience has reframed sleep as an active phase during which the brain performs essential maintenance, consolidating memories and clearing metabolic waste. The implications for understanding cognition and disease are still being worked out.
Which choice best describes the function of the second sentence in the text?
- A
It introduces an unrelated medical condition.
- Bcheck_circle
It introduces a more recent framework that displaces the rest-only model.
- C
It supports the rest-only model introduced in the first sentence.
- D
It defines the term 'sleep'.
Explanation
The second sentence reframes sleep as active rather than restful. B captures this displacing function.