How can water be used for energy ?

a. by using sunlight passively or actively

b. by placing dams in tidal areas

c. by having more windows in your home

d. by using solar panels

which of the following is not a fossil fuel

a. natural gas

b. coal

c. copper

d. petroleum

Which statement is true about the model of the electromagnetic spectrum a: it change the frequencies of light. b: it compare wavelengths of light. c: the color of light waves can be changed using the model. d: the intensities of light waves can be decreased using the model.