Why can i wiggle both eyebrows separately?

It is hereditary and also talent

Special traits sometimes allows you to wiggle one eyebrow at a time or wiggle them both at the same time just in different ways, in other words its just a special talent some people posses

D) better spellers i would think

This is first hand knowledge, top-level athletes, successful business people and achievers in all fields all  set goals. setting  goals  gives you long-term vision and short-term motivation . it focuses your acquisition of knowledge, and you to organize your time and your resources so that you can make the very most of your life.