Question

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Answer 1

This is referring to Newton's Third Law. Any force exerted on an object results in the object exerting an equal force in the opposite direction (it is important to note the equal and opposite directions for your force vectors).
1. A table resting on the earth's surface (Gravity pulls down, table pushes back)
2. Pressing hand against wall (same concept)
3. Sitting in a chair (same concept)