What is the only force that acts on a falling body when it is in free fall?

Gravity

Explanation:

Objects that are experiencing free fall, are not encountering a significant force of air resistance or as a matter of fact any other kind of forces, they are falling under the complete control of gravity.

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.