As what part of speech does the infinitive phrase function in this sentence? I want to visit Montana again next summer.

A. noun
B. verb
C. adjective
D. adverb

Why can this sentence be said to illustrate the indicative mood? insects are often harmful to farm crops. a. it states a condition contrary to fact. b. it makes a request or a demand. c. it expresses a statement of fact. d. it expresses a wish or a hope