Small intestine. The small intestine is made up of the duodenum, jejunum, and ileum. Together with the esophagus, large intestine, and the stomach, it forms the gastrointestinal tract. In living humans, the small intestine alone measures about 6 to 7 meters long.After death, this length can increase by up to half.mall intestine. The small intestine is made up of the duodenum, jejunum, and ileum. Together with the esophagus, large intestine, and the stomach, it forms the gastrointestinal tract. In living humans, the small intestine alone measures about 6 to 7 meters long. After death, this length can increase by up to half.
Obsidian: Characteristics and Properties. Obsidian is the result of volcanic lava coming in contact with water. Often the lava pours into a lake or ocean and is cooled quickly. This process produces a glassy texture in the resulting rock.Iron and magnesium give the obsidian a dark green to black color.ften the lava pours into a lake or ocean and is cooled quickly. This process produces a glassy texture in the resulting rock. Iron and magnesium give the obsidian a dark green to black color.
It is sometimes classified as a mineraloid. Though obsidian is usually dark in color similar to mafic rocks such as basalt, obsidian's composition is extremely felsic. Obsidian consists mainly of SiO 2 (silicon dioxide), usually 70% or more. Crystalline rocks with obsidian's composition include granite and rhyolite.t is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth. Obsidian is commonly found within the margins of rhyolitic lava flows known as obsidian flows, where the chemical composition (high silica content) induces a high viscosity and polymerization degree of the lava.