Which of these are stable and unstable

Which statement is true about the part of the electromagnetic spectrum that human eyes can detect? it contains only the colors of the rainbow and television waves. o it is divided into seven ranges of wavelengths. it contains ultraviolet, visible, and infrared light. it is divided into nine ranges of wavelengths.

Can someone me with questions 15 to 17 plz.

Describe the forces both attractive and repulsive that occur as two atoms move closer together.