<span>The mineral crystals in obsidian are too small to see without a microscope. This is because the rock cools so rapidly from magma that crystals barely have time to form. Obsidian is a normally happening volcanic glass framed as an extrusive molten shake. It is delivered when felsic magma expelled from a well of lava cools quickly with negligible precious stone development.</span>
I had to take a screenshot of my response since it was getting flagged for being inappropriate for some reason.
Answer:
D Microwaves
Explanation:
It has an electromagnetic radiation with wavelengths ranging from about one meter to one millimeter; with frequencies between 300 MHz (1 m) and 300 GHz (1 mm)