Why did the congress pass the land act of 1800

In order to settle the Northwest Territory.

Explanation:

The congress passed the land act of 1800 in order to give people the opportunity to buy land in the Northwest Territory directly from the federal government. The government to settle people in the Northwest territory so for that purpose the government passed this land act. This act made easier to buy land for new settlers because it cost them at suitable price and in four year installment.

i think they would live in caves or natural tunnels

raw information is your answer

~courtney