This sentence contains an apostrophe usage error. The word "it's" is a contraction for "it is," while it is being used as a possessive pronoun in this sentence. The correct form is "its," making the correct choice "a monopoly because it was acquiring many of its competitors very quickly."

This sentence does not contain an apostrophe where it is needed. The word "cars" in this sentence is plural and possessive; the clue that "cars" is plural is the use of the pronoun "they" later on in the sentence. Therefore, an apostrophe should come after the "s" (cars'). When making plural nouns that end in "s" possessive, you simply add an apostrophe to the end - nothing further. The correct choice is, "The cars' quality was so good."

It is clear that what is supposed to be meant by "its" in this sentence is the contraction for "it is." The correct form for this is: "it's." The correct choice is, "It's necessary to do the work."

This sentence misuses an apostrophe. You should never use "'s" to make a word plural. The apostrophe in "scooter's" should be omitted and no additional punctuation is necessary. The correct choice is, "scooters throughout the neighborhood."

This sentence misuses an apostrophe. There should be no apostrophe before the "s" in "its." The word "it's" is actually an contraction for "it is." Since the sentence is showing possession in this regard, "its" is the appropriate word. No other punctuation is needed or should be changed. There should be a semicolon after "masterpiece" because the sentence joins two independent clauses without the use of a coordinate conjunction. The correct answer is, "a masterpiece; its notes evoked strong feelings in everyone that listened to it."

This sentence misuses an apostrophe. An apostrophe should never be used to pluralize a noun. All other punctuation is correct. The correct answer is, "In a meeting with the managers, Rebecca." 

This sentence misuses an apostrophe. Apostrophes should never be used to pluralize a noun. The correct plural of "stock" is "stocks." The correct answer choice is, "people invest in stocks."

This sentence contains an apostrophe error. The word "bags" is possessive in this sentence; in order to make it properly possessive, an apostrophe is needed before the "s." No additional punctuation or changes are necessary. The correct choice is, "The book bag's weight was."

This sentence misuses an apostrophe. The word "it's" is a contraction for "it is." The correct word is "its," without the apostrophe, which is the possessive form of "it." No other corrections are necessary. The other choices are wrong because of other small errors in noun-adjective agreement or punctuation. The correct choice is, "Because of its constant malfunctions, the owner."

This sentence misuses an apostrophe. It is clear from the context of the sentence that the sentence is referring to many students (they key word is "them"). The correct plural, possessive form of the word "student" is students'. No other changes are necessary. The correct choice is, "The teacher collected the students' homework every day."