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.
The heart and blood vessels (arteries, capillaries, and veins) are called the cardiovascular system. The cardiovascular system carries blood throughout the body. The heart pumps blood through blood vessels called arteries and then through smaller blood vessels called capillaries to each organ and tissue in the body.