This lesson discusses three types of physical activities: aerobic activities, muscle strengthening activities, and bone strengthening activities. Aerobic activities increase heart and breathing rates through activities like jogging and swimming. This delivers more oxygen to muscles, allowing sustained activity. Muscle strengthening activities like pushups cause muscle damage through contraction, but make muscles stronger through repair. Bone strengthening activities like basketball apply physical stress through muscle contraction, stimulating bone growth and increasing density. The lesson emphasizes benefits like reduced disease risk and everyday physical ability. It explains FITT principles of frequency, intensity, time and type for effective exercise.