Water
water is composed of hydrogen and oxigen gases
Article is a HTML5 semantic element used to specify independent self contained content, it is considered independent from rest of content in website, mostly it is used in forums, blogs, newspapers etc.
<article>content</article>
You can define one or more than one articles in a document.
Open notepad or any other text editor, follow the following points.
save file with name task.html or task.htm and then open it using any browser and see results.