[ ]transport moves substances from an area of high concentration to an area of low concentration.

The answer is Diffusion.

Explanation:

Diffusion is a movement of molecules(substances) from a region of high concentration to a region of low concentration down a concentration gradient.

heat or electricity in the atmosphere- c.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.