Which farming invention of the 1800s reduced the number of people needed to work in the fields?

How might the first nations have reacted when they saw that the europeans were moving onto their lands and disrupting their way of life? (this was when the europeans came to canada and tried to claim land to themselves)

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 massacre at sand creek was an attack by a colorado militia on peaceful american indians. a colorado militia on a group of dakota warriors. american indians on peaceful white settlers. federal soldiers on a group of cheyenne warriors.