Finn listed two of the three steps involved in gene therapy.
which step should he also include, and where?

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.

they are made of gases.

they have a spherical shape.

they make energy through fusion.