The difference between the speed of sound n air at 0°c and the speed of sound in air at 20°c is a. cooler air molecules move more slowly and respond less readily to the energy of a sound wave. b. cooler air molecules move more quickly and respond less readily to the energy of a sound wave. c. cooler air molecules do not move and respond less readily to the energy of a sound wave. d. cooler air molecules move more randomly and respond less readily to the energy of a sound wave.