What is an advantage of using coal power over solar power to generate electricity

Which statement best describes how private industry decides where to spend the money on research and development

Which of the following are properties of mechanical waves? check all that apply ⭕️ particles of the medium move back and fourth, but do not move with the wave. ⭕️ the particles of the medium always move parallel to the wave motion. ⭕️ wave motion begins with a disturbance in the medium. ⭕️ waves transport energy from a source outward, away from the source.

The difference between a red shift and a blue shift has to do with wavelength frequency. t or f