When does upward growth of cities typically occur? a when water resources are limited
b. when waste production is a problem
С. when available land is limited
d when population exceeds 100,000

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

What is a he difference between earthquake magnitude and intensity

Which of the following is also known as the eastern european plain and stretches from eastern poland to the ural mountains? russian plain? west siberian plain? central siberian plateu? eastern highlands?