How have world economies changed during the moder era

If one thinks illegal immigrants should become american citizens, should they become american citizens automatically or should there be a waiting period?

Marine exptoration of oil uses seismic waves to locate oil in the seabed. what is a negative impact from seismic waves on the aquatic ecosystem of the ocean? a. seismic waves kill microoganisms b. seismic waves disrupts the sand and causes seafloor erosion c. seismic waves have virtually no adverse affects on marine life d. seismic waves damage the sonar that dolphins and whales use to orient themselves underwater

Why did european nations face financial challenges after world war 1?