Gastrointestinal tract
The small intestine begins at the duodenum and is a tubular structure, usually between 6 and 7 m long. Its mucosal area in an adult human is about 30 m. Its main function is to absorb the products of digestion (including carbohydrates, proteins, lipids, and vitamins) into the bloodstream. There are three major divisions:
Penis
As with any other bodily attribute, the length and girth of the penis can be highly variable between mammals of different species. In many mammals, the size of a flaccid penis is smaller than its erect size. In the realm of absolute size, the smallest vertebrate penis belongs to the common shrew (5 mm or 0.2 inches).