Needed to form possessive nouns and contradictions is called

I believe the answer is: You need an apostrophe to to form contractions and possessive nouns.

in general, the aposthrope tend to be used as closing single quotation. But, if the aposthrope is placed after a noun followed by "s" it would form a possessive nouns. Example:

This year, The state of Orlando require self-defense class as a part of high school's curriculum.

answer; the sound of a train whistle makes a woman think of an old friend; //

the smell of grass makes a by feel that spring is the best; (apex);