The correct answer is: Nobody knows everything he or she can about the brain.
Explanation:
There are different types of pronouns. They help to replace the noun in a sentence. In this case, the word "<em>Nobody</em>" is part of the indefinite pronouns and they are always used in the singular. So, it is necessary to change the personal pronoun "<em>They</em>" for the singular "<em>He or She</em>".
The answer is A. Hope this helps!
If we are referring to academic vocabulary, we mean to say the words or group of words that are used in the academic dialogue. These words are not common and are not frequently encountered in daily conversations. We can change the word awful to dreadful.
