Electromagnetic Waves of Various Frequencies Reach Earth from Distant Parts

Multiple Choice

Electromagnetic waves of various frequencies reach Earth from distant parts of the universe. Which of the following can be inferred from this?

A) The wavelengths must be very short.
B) A single material must fill all of space.
C) These waves can travel without a medium.
D) The speed of these waves is 300,000,000 m/s.