1 Pepsin is the main gastric enzyme. 2  It is produced by the stomach cells called chief cells in its inactive form pepsinogen, which is a zymogen. 3  Pepsinogen is then activated by the stomach acid into its active form, pepsin.
Single (music) In music, a single, record single or music single is a type of release, typically a song recording of fewer tracks than an LP record, an album or an EP record. This can be released for sale to the public in a variety of different formats. In most cases, a single is a song that is released separately from an album, although it usually also appears on an album. Typically, these are the songs from albums that are released separately for promotional uses such as digital download or commercial radio
Debut is an artist/bands first ever single off of their first CD. Single is any single released after the debut. a single is just a song that comes out in the radio or in video. debut single is like new artists and the one new song they put out and reglusr single is ...just a single....