I believe the correct answer is sound waves. It is the sound waves that always need matter or a medium in order to propagate. Sound waves are mechanical waves that has different characteristics to electromagnetic waves which does not requires a medium to travel. Mechanical waves depend on the particles interaction for it to travel hence a medium is needed.
answered: Guest
a solution is always transparent, light passes through with no scattering from solute particles which are molecule in size. the solution is homogeneous and does not settle out. a colloid is intermediate between asolution and a suspension. while asuspension will separate out a colloid will not.
answered: Guest
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.
Which statement is true according to the kinetic theory? a. molecules of different gases with the same mass and temperature always have the same average density. b. molecules of different gases with the same mass and temperature always have the same average volume. c. molecules of different gases with the same mass and temperature always have the same pressure. d. molecules of different gases with the same mass and temperature always have the same molecular mass. e. molecules of different gases with the same mass and temperature always have the same average kinetic energy.