Which type of scientist would study the earth's atmosphere?

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

One disadvantage that darwin faces today is w. enemy attacks x. natural disasters y. lack of land bridge z. high population density

How far is a geographic second? a.) around 100 feet b.) around 1,000 feet c.) around 5,000 feet d.) none of the above