"surely the opening vistas of space promise high costs and hardships, as well as high reward."

which of the following is the best replacement for the word "vistas" as it is used in this context?
a.) advancements b.)missions c.) offerings d.)visions

b.science

explanation:

the answer is:

when will (v) the books (n) be (v) due?

nouns refer to people (other than pronouns), places and things, whereas verbs describe actions and are usually part of the predicate of a sentence. finally, pronouns can work as nouns and identify the participants in speech.

in the example sentence, "will" is a verb part or auxiliary verb, "be" is an infinitive verb and "books" is a plural noun.