Why is the actual movement of stars hard to see?

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.

Which did many cities ermerge along fall line in southern us

Which is a mathematical statement consisting of a hypothesis and conclusion that has to be proven true? definition