Biodegradable polymer which, edible films have gained more attention due to their environmentally-friendly characteristics, vast variety and availability, non-toxicity, and low cost. Biodegradable polymers have a long history, and since many are natural products, the precise timeline of their discovery and use cannot be accurately traced. One of the first medicinal uses of a biodegradable polymer was the catgut suture, which dates back to at least 100 AD. The first catgut sutures were made from the intestines of sheep, but modern catgut sutures are made from purified collagen extracted from the small intestines of cattle, sheep, or goats. The concept of synthetic
Triangle (musical instrument) Triangle (musical instrument) The triangle is an idiophone type of musical instrument in the percussion family. It is a bar of metal, usually steel but sometimes other metals such as beryllium copper, bent into a triangle shape. The instrument is usually held by a loop of some form of thread or wire at the top curve. "It is theoretically an instrument of indefinite pitch, for its fundamental pitch is obscured by its nonharmonic overtones." Triangle has a prestigious history. The triangle in its ancient form had rings strung to the lower bar. Yet the first mention we find of a