Top Ten Powerful Nations 2013 (According to Global Presence). Top Ten Powerful Countries Ranking (2012). NOTE: National Power Index (NPI) 2012 is a comprehensively revised version of the previous National Security Indexes published in Indiaâs National Security Annual Review (INSAR) series since 2002.op Ten Powerful Nations 2013 (According to Global Presence). Top Ten Powerful Countries Ranking (2012). NOTE: National Power Index (NPI) 2012 is a comprehensively revised version of the previous National Security Indexes published in Indiaâs National Security Annual Review (INSAR) series since 2002.
Overview. When you take in food, it's the job of your digestive tract to break that food down into smaller pieces through mechanical digestion, and then break larger molecules into smaller ones through chemical digestion.
Chemical digestion that occurs in the stomach is mainly via enzymes and hydrochloric acid. The stomach secretes pepsinogen which turns into pepsin and breaks down proteins.The hydrochloric acid provides a low pH level in which the enzymes can thrive.hemical digestion is the breaking down of food particles through chemical reactions. Chemical and mechanical digestion combine to process food, absorbing nutrients and minerals and discarding the waste. Very little mechanical digestion occurs outside of the mouth.