When the air under the envelope is heated, the balloon lifts. which of the following statements is true? a) hot air balloons use radiation to rise b) hot air balloons use conduction to rise c) hot air balloons use convection to rise d) hot air balloons use air resistance to rise

Ultraviolet radiation is dangerous because it has a high enough energy to damage skin cells. what is the best explanation of the relationship between wavelength and wave energy? a) wave energy is related only to frequency, not wavelength. b) longer wavelengths have lower frequencies but higher energy. c) the shorter the wavelength, the lower the frequency and the higher the energy. d) the shorter the wavelength, the higher the frequency and the higher the energy.