time for some gravity! except if have no idea what’s going on, could someone ? : )

Heat from the sun reaches earth to a. radiation b. convection c. conduction

What does si stand for,when referring to a system of measurement

If a negatively charged particle is placed at rest in an electric potential field that increases in the positive x-direction, what will the particle do? a. accelerate in the positive x-direction b. remain at rest c. accelerate in the negative x-direction