Asthma, lung cancer are two.
Red blood cells pick up oxygen in the lungs. Blood travels away from the heart and lungs through the arteries. Red blood cells drop off oxygen to the cells through tiny tubes called capillaries. Blood then returns to the heart through the veins and the cycle begins again.
Hi,
9. What is the amount of fluoride concentration in water that's considered safe for the prevention of dental decay?
D. 1 part per million
