Why was it significant that General Washington was pushed back to Pennsylvania?

The internal combustion engine was an innovation of

Why did un coalition troops battle iraqi forces in 1991? iraq had invaded saudi arabia, along with its other border nations.iraq had invaded kuwait, which was a major source of the world's oil.the united nations wanted to remove saddam hussein from power.the united nations wanted to prevent the trade of illegal drugs.

Which pre inca culture was responsible for the geoglyphs