The sentence that accurately describes the relationship between the theory of Universal Grammar and the acquisition of a second language is "The theory of Universal Grammar supports language acquisition because all languages share a similar structure." According to this theory, there are universal principles, shared by all languages, and parameters that can vary between languages. So, a second language learner has to set the values of a parameter. For example, the pro-drop parameter has two values, the pro-drop in the case of the Spanish language, in which a subject or object pronoun can be omitted, and the non-pro drop in the English language, in which the pronoun cannot be omitted.