Red blood cell the centre of 0.8–1 µm, being much smaller than most other human cells. These cells have an average volume of about 90 fL with a surface of about 136 μm, and can swell up to a sphere shape containing 150 fL, without membrane distension. Adult humans have roughly 20–30 trillion red blood cells at any given time, constituting approximately 70% of all cells by number. Women have about 4–5 million red blood cells per microliter (cubic millimeter) of blood and men about 5–6 million; people living at high altitudes with low oxygen tension will have more. Red blood cells are
Under a Blood Red Sky Under a Blood Red Sky Under a Blood Red Sky is a live album by Irish rock band U2, produced by Jimmy Iovine and released on 21 November 1983. Along with its companion concert film, "", the release helped establish U2's reputation globally as a live act. The album consists of live recordings from three shows on the band's War Tour, from Colorado and Boston in the US and from Germany. An accompanying concert video entitled "U2 Live at Red Rocks: Under a Blood Red Sky" was released the following year. The film was recorded entirely at the outdoor Red