Which of following describe(s) a way in which radio waves can carry energy?
A. through rock layers, from a source, to a reflector, and then to a receiver
B. through the Earth's atmosphere, from a broadcast tower to a receiver
C. all of these

C. All of these

Explanation:

All of these are ways in which radio waves can carry energy. Radio waves, like other forms of electromagnetic radiation, can travel through matter as well as the vacuum of outer space.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.

answerspecific gravity;