fill in the blank question\nin this diagram, the parts of the electromagnetic spectrum are arranged in order…

Brief Explanations:

The electromagnetic spectrum can be arranged by wavelength or frequency. In this diagram, as we move from left (radio waves) to right (gamma - rays), the wavelength values (e.g., (10^{3}), (1), (10^{- 3}), etc.) are decreasing. Wavelength ((\lambda)) and frequency ((f)) are related by the formula (c = \lambda f) (where (c) is the speed of light). When wavelength decreases, frequency increases. But since the scale on the diagram shows numerical values of wavelength decreasing from left to right, the key here is wavelength.

Answer:

wavelength