Read the passage.
The Neolithic Revolution

Read these sentences from Paragraph 10 of the passage.

For example, some farmers learned that fire could help them grow more grain. They cleared land by cutting trees, bushes, and grass, and then burning them. The remaining ashes left the soil rich in nutrients. This kind of farming is called slash-and-burn agriculture, and it helped early people maintain fertile soil.

What does slash-and-burn agriculture mean?

the practice of leaving a plot of land empty so the soil's nutrients regenerate

a method of chopping down trees and brush and burning them to create rich soil

a technique of burning dried brush to prevent wildfires

the process of setting fire to trees and brush to clear the land