The answer is letter A.
Biking or bicycling is a form aerobic exercise that develops cardiorespiratory fitness. This is because the heart and lungs are the important organs that function when this activity is being done. Biking for 30 minutes to more than a few hours will inhibit the strengthening of the muscles of the heart and the ability of the lungs to convert unoxygenated blood into oxygenated blood. If you engage in this activity on a regular basis, you will notice and improvement in your performance.
Tapeworms and lice are examples of parasites that can cause diseases in humans.
<span>B. Cilia and white blood cells</span>
