Answer:
a. relied upon crops that they grew
Explanation:
The pestle for mashing taro that is estimated to be 8,000 years old suggest that the people of Papua New Guinea were relying upon crops they grow for a very long time now. The taro is crop that requires well drained soil and lot of water, so the wet tropical climate of Papua New Guinea allowed for this crop to thrive. In order to not be reliant on mother nature, the people started to plant this crop in order to produce enough food for themselves, and so they did, solving their biggest problem.