The incorrectly punctuated sentence is: She wants to buy film, and chewing gum. This sentence is incorrect because there should be no comma after the word film. A comma could be used if there were two independent clauses: She wants to buy film, and she wants to buy chewing gum. A comma could also be used if there were three objects she wanted to buy: She wants to buy film, chips, and chewing gum. However, there is no need to add a comma for the sentence as it is currently written. The next incorrectly punctuated sentence is: Reesa is wearing a dark, green sweater. This sentence is incorrect because there should be no comma after the word dark. The adjective "dark" is telling more about the color "green" -- it is a dark green sweater. Therefore, no comma is necessary.
