Agriculture is deliberate tending of crops and livestock to produce food, feed, fiber, and fuel. Primary Economic Activities are farming, fishing, ranching, mining, and forestry. Secondary Economic Activities are manufacturing into things like toys and chemicals.
Subsistence Agriculture is when people grow enough food for themselves and don't sell it. This type of agriculture has been most prominent throughout history. Some subsistence farmers use a method called shifting cultivation, which is moving from place to place for better land.