Answer:
The element of surprise and other stuff.
Explanation:
They were able to enter the city. The Aztecs thought that Cortes was a god. Also they had guns, cannons,swords, and horses. They thought the horse wold eat them alive. Also, the Europeans brought diseases such as smallpox which weakened the Aztecs greatly and made the battle easier.
The answer is oxygen .
Other planets don't provide life and air
Free elections were held in Iraq
Most colonies lacked human labor, therefore, they used slaves to work on plantations in the new found colonies.