In paragraph 1, what does the author imply about changes in the African environment during this time period?

• The climate was becoming milder, allowing for a greater variety of crops to be grown.
• Although periods of drying forced people south, they returned once their food supply was secure.
• Population growth along rivers and lakes was dramatically decreasing the availability of fish.
• A region that had once supported many people was becoming a desert where few could survive.

This is a multiple choice.