Ummm who's good at
what causes the convection cell to turn up at point a?

why do you think this convection cell might affect the crust material above it? ?

the answer to your question is b

the framers of the constitution insisted that federal judges be nominated instead of elected due to their desire to have judges above the shifting whims of the masses.

the hope, whether achieved or not, was that federal judges would only be beholden to the law and that by not having judges be elected, they would be protected if that law dictated an outcome that ran counter to popular opinion.