Question

what characteristic do all parts of the electromagnetic spectrum share? they have the same wavelength. they have the same frequency. they interact in the same way with any matter. they travel at the same speed through empty space.

Explanation:

All parts of the electromagnetic spectrum, from radio - waves to gamma - rays, travel at the speed of light ($c = 3\times10^{8}\ m/s$) in a vacuum. Wavelengths and frequencies vary across the spectrum, and different parts interact differently with matter.

Answer:

They travel at the same speed through empty space.