An ambiguous reference occurs when a pronoun may refer to two or more antecedents refers to an unknown antecedent modifies an adjective, adverb, or verb functions as the object of a preposition

may refer to two or more antecedents

right angles are formed by perpendicular lines. if the lines would extend, to make two intersecting lines, they would form four right angles.

both the address and the poster use diction to convey their message. diction is defined as a style of writing or speaking based on the types of words chosen in order to send a message. parallelism is when a similar sentence structure is used for several sentences on a text; roosevelt's address doesn't follow that. repetition has to do with repeating a word or sentence in order to emphasize and idea, however neither the poster nor the address use repetion. finally, the address doesn't use images to convey a message.