How did the united states acquire puerto rico? a. invasion b. treaty c. purchase d. annexation with military involvement

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

The internal combustion engine was an innovation of

Why did president johnson decide not to run for reelection in 1968?