How Can a Plant Kill?

People kill. Animals kill. Animals and people kill for food, or they kill their enemies. People and animals can move around and find something to kill. They can run away from an enemy. They can kill it if it is necessary. Many kinds of animals eat plants. The plants cannot run away from enemies. Some plants make poison. If an animal eats part of the plants, it gets sick or dies.

Animals learn to stay away from these plants. They are many kinds of plants that make poison. Most of them grow in the desert or in the tropics. Today farmers use many kinds of poison on their farms. Most of these poisons come from petroleum, but petroleum is expensive. Scientists collect poisonous plants and study them. Maybe farmers can use cheap poison from plants instead of expensive poison from petroleum.