What the excerpt is trying to convey is that, with the current generation we are so preoccupied with own self-interests. We value vanity, self and glory without considering the individuals we face as we walk, as we talk and as we engage. The passage reinstates that individuals have to get back and introspect about not their own gratifications and egotistical desires but the welfare with others, even though it is innate and inevitable that we always point to the ego.
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>".
I hope to make a legacy in this world someday.
The eave of my house fell off during the hirrican last night.
