The answer would be the ozone layer. <span>A layer of ozone in the upper atmosphere absorbs </span>UV radiation<span> and </span>prevents<span> most of it from </span>reaching<span> the </span>Earth<span>. ... This means that more </span>ultraviolet radiation<span> can pass through the atmosphere to the </span>Earth's<span> surface, particularly at the poles and nearby regions during </span>certain<span> times of the year.
Muscles and organs derive the most benefit from the blood that flows in the arteries and capillaries because they obtain food substances and oxygen while releasing wastes.
