Question 2
If action and reaction are equal in magnitude and opposite in direction, why do they not cancel out and leave nothing in the world able to move?
The right answer is the one marked above.
Because they act on two different objects, not on the same one. This is the most important point in the third law.
For two forces to cancel, they must act on the same object. That is what happened with the pushing force and the friction on the table — those are balanced forces.
An action–reaction pair acts on different objects, so each object moves according to the force applied to it. And the reaction is not later than the action — they happen together.