I need help ill give points pls help

What is driving behind plate tectonics (plate movment)? a) gravity only b) inertia c) convection and gravity d) the sun theres no option for science so i picked chemistry. plz

For ai it's atomic number is 13 and it's mass number is 27 how many neutrons does it have

In a ni-cd battery, a fully charged cell is composed of nickelic hydroxide. nickel is an element that has multiple oxidation states. assume the following proportions of the states: nickel charge proportions found 0 0.17 +2 0.3 +3 0.33 +4 0.5 (a) determine the mean of the nickel charge. enter the answer to 2 decimal places.(b) determine the cumulative distribution function of nickel charge.