The Aksum Empire was the result of two world hubs sharing their collective learning about agriculture, and rose to become a great power in the ancient world because it formed a crucial link between East and West on the supercontinent of Afro-Eurasia.
The purpose of the Louisiana purchase in 1803 was to give the United States more control of the Mississippi River, and the port city of New Orleans, which were both used by farmers to ship their crops and get paid.
The Crusades
These were a series of military campaigns by western Europe Christians in the high middle ages. the purpose was to liberate the holy land from Muslim occupation and rule.
Answer: I believe the answer is the first one, rain forests, deforestation, water cycle.
Explanation: I think so because the words in that answer include the important keywords of the paragraph above.
