Respuesta :
The 4th one. The first has unessential commas that separate pertinent info of the sentence. 2nd needs a comma after was. 3rd needs a comma after textbook. 5th needs the exclamation mark before the quotation mark.
Answer :The polar bear, which is an endangered species, lives mostly in the arctic region.
Allusion is a figure of speech that refers to another work in order to explain an idea.