Which of these is not a characteristic of a mineral? a. naturally occurring, inorganic substance b. crystalline structure that forms a geometric shape c. always a solid; never a liquid or gas d. a variable chemical composition

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.