Melting is a physical change in matter, so it doesn’t change the chemical makeup or chemical properties of matter. a: true b: false

is this site ment for k12

the ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (uvr) from the sun, protecting life on earth from its potentially harmful effects. when the sky is clear, there is an inverse relationship between stratospheric ozone and solar uvr measured at the earth's surface.

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.