Riding a bike is an example of Newton's third law of motion because the force needed to pedal a bike forward, which is the force that the tire exerts on the ground, is equal to the force of the ground pushing against the tire. The real-world example of riding a bike can also be used to demonstrate Newton's first and second laws of motion.
Newton's third law of motion explains that for every action, there is an equal and opposite reaction. The third law of motion can also be seen by a person balancing while riding a bike. As riders shift their weight to the left, they must exert equal pressure from the opposite direction to maintain the bike's balance. Newton's third law of motion helps explain why it is easier to balance on a moving bike, where an opposite force can be applied through manipulating the front tire using the handlebars, than it is to maintain balance on a stationary bike that is not receiving a force from the ground while moving.
Other real life examples of Newton's third law of motion can be seen in the movement of an elevator, the firing of a gun, the spraying of a firehose and the rotating of garden sprinklers.