1. which of the following is true and radio waves?
A. they have high energies
B. they reveal hot gasses
C. they can penetrate dist clouds
D. they have short wavelengths

2. which of the following is used in medical imagery?
A. ultraviolet light
B. blue light
C. radio waves
D. X-rays (I think this is it)

3. which of the following has the longest wavelength?
A. Red light
B. radio waves
C. microwaves (I don't know if this is like the kitchen appliance or something else)
D. infrared light