Final answer:
The force that pulls objects towards Earth's center is the gravitational force, while the electric force is crucial in holding an atom together.
Step-by-step explanation:
The force that pulls objects down towards the center of the Earth is the gravitational force. Among the options provided, gravitational force is the one that is always acting upon objects at or near the Earth's surface. This force is responsible for the structure of galaxies, maintaining the orbit of celestial bodies, and is also the force experienced by an object in freefall when no other forces are acting on it. On the other hand, the electric force is crucial in holding an atom together, representing the attraction between the positively charged nucleus and the negatively charged electrons.