A highly detailed electron microscope image of collagen fibers found in the lung.

A black and white diagram of the human lungs. The image shows a brief outline of the human chest, the trachea or windpipe as well as the bronchial tubes and of course both lungs.

The fastest land mammal in the world, the cheetah (Acinonyx jubatus) has many adaptations that allow it to sprint across the plains. Its rangy frame supports long limbs and a deep chest cavity, and this species has a small waist and an...

" Ethnolinguistic Groups - Almost all inhabitants of mainland China are of Mongoloid stock, and ethnic distinctions in the country are largely linguistic rather than racial. The Han comprise nearly 95 percent of the population; the...