How does the possessive formed if the noun is plural and ends in -s ? a) adding an apostrophe after the -s b) adding an apostrophe and an -s after the -s c) adding apostrophe and an -es after the -s d) adding nothing

Your answer would be A) Adding an apostrophe after the s.  Such as if someone's name ended with an S. Example being, Alexis. So you would say Alexis' sushi.

true. the definition explains it: a word or phrase that modifies or qualifies an adjective, verb, or other adverb or a word group, expressing a relation of place, time, circumstance, manner, cause, degree, etc. this is a dictionary definition that i have looked up in a dictionary.

cavern or cave

i hope this