How many political parties were allowed in the Soviet Union?

Ineed answers 5 and 6 on my social studies homework reply to this question i posted

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

In a story containing the following points, which would likely occur last?