Select the most appropriate option to fill in blank number 1.
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. but.
The sentence contrasts two conditions: the stillness of the body during sleep and the activity of the brain.
The word 'but' is used to introduce a contrasting idea, making it the most appropriate connector.
Example: 'The body is still, but the brain is active.'