What is the atomic number of 24 and 12 Mg

Idon’t quite understand this problem

If a simple machine reduces the strength of a force, what must be increased?

Selma made a diagram to compare convection and radiation. which label belongs in the area marked x? must involve temperature differences between substances or objects only occurs when molecules are in direct contact involves the movement of fluids based on density differences can occur where there is little or no matter