To what extent are humans responsible for changing landscape​

The physical processes that create most of earth's physical features, including mountains, are known as

About 140,000 japanese died in this japanese city when americans dropped an atomic bob at the end of world war ii

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