Why do political discussions of the twentieth century tend to fixate on Fascism or Communism and not on colonialism?

What are seismic dampers and why are they important?

Which of the following is an example of a policy that may be implemented by a business that has trouble with employees using the internet for their own personal needs? a. all employees will have to take a safety training class. b. employees caught using the internet for personal needs will have to take a professional development class. c. personal interviews will be conducted to find out who is using the internet for personal needs. d. employees will be monitored, but nothing will happen if their employer catches them using the internet for personal needs.

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