As you already control more than 10 percent of your brain nothing significantly different would happen.
Magic would happen.
Lefty's would rule the earth.
Your brain would get damaged and you would die.
We would be able to control things with our mind and basically know everything. (If you don't believe me, then its still true)
died
Yes
You would be named Brayden or Elliott
You would suffocate, have brain damage, and die.
You would instantly die.
Being alive would be sufficient to use 100% of your brain, however you don't nor would you want to use 90% of your brain at once.
The Brain Wouldn't Tell The Heart To Beat So You'd Die.
It would simply cease to work.