What causes lightning? a. thunder c. rising warm air b. an electric discharge d. air masses meeting

What type of electromagnetic wave is used in security pens? a. x-rays c. microwaves b. visible light d. ultraviolet radiation select the best answer from the choices provided

The discovery that the universe appears to be expanding led to a widely accepted theory called a.) the big bang theory b.) the doppler effect c.) hubble’s law d.) solar nebular theory e.) the seyfert theory

Ryan is examining the energy of the particles in a bar of gold. what is ryan most likely studying?