A: Could Have. You're Welcome :)
An interjection is a word used to show feeling. Interjections are words such as:<em> yikes, ouch, </em>etc.
Prepositions are: <em>at, on, in, </em>etc. and they don't show any feeling.
Pronouns are: you, me, them, he, etc.
Conjunctions are: and, or, while, etc.
As for the first part, Cost, Radiation exposure to humans, No water or heat, and unfit soil. As for the second, Astronomers, Botanists, and obviously your fair share of rocket scientists and math matitions for the way up.
A. We spent the rest of the night hooting, hollering, and creating good-natured havoc.
