Correct answer # 2: The world's nations must cooperate; one nation cannot solve the world's problems by itself.
When you connect two related independent clauses or sentences you use a semicolon. Both sentences should be completed grammarly writtend and with a connection. Make sure you do not write a capital letter after the semicolon, unless it is a proper name.
Answer # 3 is incorrect as there is a capitalized word
Answer # 1 it is incorrect to use "for" as the sentence is grammarly completed
If this is asking for a personal opinion, then no. I do not believe there is any relationship or connection between sanity and intelligence because someone’s mental state or background doesn’t define their intelligence or thinking patterns. Some studies done over mental disorders such as BPD (borderline personality disorder) have found sufferers to be more intelligent and, ironically speaking, happier than the average person.
Make sure to do your chores or things you need to do ;)
Its b.
Cause it is. and how would you if it was wrong.HAHAHA