Permutation is an ordered arrangement of a group of objects. 1  The permutation of n objects taken r at a time is represented as nPr. 2  The permutation or arrangement of 9 different balls in 3 different rows can be done in 9P3 = 504 ways.  The permutation of n objects taken all at a time is represented as nPn = n!.
Collagen is a protein that is part of cartilage, bone, and other tissues in animals and humans. People use collagen from chickens for medicine. Chicken collagen is used to treat joint pain associated with many types of arthritis and surgery, as well as back pain, neck pain, and pain following injury.
There are at least 16 types of collagen, but 80-90% of the collagen in the body consists of types I, II, and III. Type I collagen fibrils are stronger than steel (gram for gram). Collagen is most commonly found within the body in the skin, bones and connective tissues. The word collagen is derived from the Greek kolla, meaning glue. Collagen gives the skin its strength and structure, and also plays a role in the replacement of dead skin cells.