On a percentage basis, what type of sequence comprises the most of the human genome? what type of sequence comprises the least?

Non-coding ... exons. Most part of the human genome does not code for proteins. They include what was then referred to as ‘junk DNA’. Noncoding regions contain introns and transposable elements, telomeres, and centromeres. Exons, on the other hand, are the regions of the DNA that code for proteins that are responsible for the normal body functions.