Final answer:
The presence of a normal force between two objects requires them to be in contact, making the statement true. Polarization can occur without direct contact, making the statement false. And a gravitational force exists between any two masses, regardless of the distance, making the first given statement true.
Step-by-step explanation:
The statement that normal force exists between any two objects only when they are touching is true. Normal force is a contact force that acts perpendicular to the surface of contact, opposing other forces such as gravity. Without contact, there is no normal force.
Charging an object by polarization does not necessarily require touching it with an object carrying excess charge, so the statement is false. Polarization can occur simply by bringing a charged object close to an insulator, causing a separation of charges within the insulator without direct contact.
Two objects will have a gravitational force between them as long as they have mass, irrespective of their charge or the presence of other forces. Therefore, two hydrogen atoms 10 cm apart would experience a gravitational force, though miniscule, making the first of the given statements true.