Is the mississippi river, the columbus river, or the rio grande river closest to illinois?

The earth is composed of three different chemical layers: core, mantle and crust. the formation of these layers was from a process called

What are the answers for the following questions?

Which of these is a drawback of using natural gas? a. it is fairly safe for use in homes. b. it burns more cleanly than crude oil products. c. scientists have developed new ways of extracting it. d. during its extraction, groundwater can be contaminated.