Question

The process of ensuring that web pages coded with new or advanced techniques still are usable in browsers that do not offer support for the newer features is called: validation valid enhancement progressive enhancement optimization

Answer 1

The answer is Progressive Enhancement.

Progressive Enhancement remains to be a very powerful methodology that allows designing of web pages with more features. It is a strategy that builds web pages for the most modern web browsers. They then ensure that these modern web browsers work perfectly well with less functional browsers