Final answer:
The electromagnetic spectrum represents the complete range of frequencies of light energy, including radio waves to gamma rays. It encompasses all types of electromagnetic radiation and different parts of the spectrum have various applications.
Step-by-step explanation:
The answer to the student's question, 'The ________ represents the complete range of frequencies of light energy from radio waves to cosmic rays,' is D. electromagnetic spectrum. The electromagnetic spectrum includes all types of electromagnetic radiation, which varies in terms of frequency, wavelength, and energy. The spectrum ranges from low-frequency radio waves to the very high-frequency gamma rays. Visible light—the light we see with our eyes—only represents a small portion with wavelengths between approximately 400 nm (violet) and 700 nm (red). Beyond visible light, the spectrum extends to include infrared, ultraviolet, X-rays, and much more, each with unique properties and applications.