Changes with Age. In most cases, a person's normal respiratory rate will change with age; younger adults, children, and babies will typically have faster respiratory rates, because as people age, their breathing usually slows down.
Modic changes are pathological changes in the bones of the spine, the vertebrae. These changes are situated in both the body of the vertebrae and in the end plate of the neighboring disc.
Changing the electronic structure usually means that a bond has broken or formed, which is a chemical change. However, certain types of color changes are physical. For example, when you heat a piece of metal and it begins to glow red, then orange, then yellow as you increase the heat, that's a purely physical change.