Why we need each section of prologprogram?

Prolog program are used in the artificial intelligence and the web development in a systematic manner process. As, it is also sometimes known as declarative language which basically consist of some facts and list. Prolog program are divided into the sections that are:

Domain sections Clauses sections Predicates sections Goal sections

We need each section of the prolog program because all the sections introduced the systematic program and performed there particular functions so by using all these processing steps an efficient function are formed.