Most of the worlds land is used for

Which of the following terms describes the layers of air surrounding the earth ?

Can someone me choose a broad topic and area of focus i am really doing this as a tally to see which one most people pick ok water pollution global warming endangered species atmosphere for the !

Some gamma ray bursts are hypothesized to come from mergers of neutron stars or black holes. if this hypothesis is correct, what else should we in principle be able to detect from such mergers? a. gravitiational waves b. x-ray bursts c. significant disruption of gas thousands of light-years away in the surrounding galaxy d. an "afterglow" of bright visible light, lasting for weeks