Im pretty sure a cinder-cone volcano
Light moves in a straight line except at surfaces between different transparent materials, where its path bends.
A - its condensation and gas particles have a higher kinetic energy
The frequency of a photon of red light with wavelength 4.50 x 10−7m is 6.67 x 1014Hz
68.7g
molar mass of Ba(137.327)x (.500)= 68.6635
.500 has 3 sig figs.