According to the Bohr model, the wavelength of the light emitted by a hydrogen atom when the electron falls from a high energy (n = 4) orbit into a lower energy (n = 2) orbit.
A network of arteries and veins also carry blood throughout the body: Arteries transport blood from the heart to the body tissues. Veins carry blood back to the heart.ow the heart works. The heart is a large, muscular organ that pumps blood filled with oxygen and nutrients through the blood vessels to the body tissues. It's made up of: Four chambers. The two upper chambers, the atria, receive and collect blood.
Knee injuries are common among active kids and teens, especially athletes. A torn medial collateral ligament (MCL) â a ligament that helps give the knee its stability â is one of the more serious injuries. Kids who tear their MCL tend to play contact sports, like football and soccer.