A header must be created at the top right hand corner, and this must have your name, a space and the page number. The section headings used to make the essay readable are not sacrosanct. So, you can twist and use them as you deem fit. You can do the numbering with the Arabic number or the roman numerals. But you must insure that you put a period and a space after the numbering before you write the name of the part of the book. When it comes to headings for books, you will not get any specific system as prescribed by mla. If you decide to make use of one level or system of headings for all distinct sections, you must make them to have a semblance in grammar. This entails that if you use short phrase pointers for headings, then it must be the same for all the headings. This means you should not use a short phrase for some and full sentences for others.
Being one of the most widely spread elements in existence, silicon throughout the history of human civilization played a very important role in architecture and construction, because it served as a component of many building materials, such as glass, concrete and stone. The most dramatic impact of silicon on the human existence and the world’s economics was caused, however, only in the 20th century, when it became widely used in the production of semiconductors and transistors that have later evolved into computer chips, laying a foundation for the whole information industry that is one of the most characteristic features of modern times.