What are the basic differences (tags and attributes) between HTML 5 and lower versions. Flash, Jquery and CSS is still play an important role with HTML 5?

Does it eliminate the requirement of mobile websites or still we need a separate mobile version website?

These are some basic questions when we ask about HTML5, websites in mobile version and responsive web design.

Your expert view is most welcome. You can help thousand of people by answer these questions in details.

Thanks