The answer is A. Robert Fulton, who, although he wasn't the first one to come up with the steamboat idea, Fulton built the first safe practical model of the steamboat.
Answer:
Farmers needed to dispose of farm-animal waste to keep water supplies clean. Fertilizer made the soil capable of growing plants brought from other continents. Adding fertilizer to the soil prevented farmers from having to use slash-and-burn techniques.
Explanation:
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