According to Newton, the force of gravity is a two-way tug between any two objects. It works with anything—any matter at all. The matter can be a tiny bit of a thing, as small as a speck of stardust. It can be a huge collection of material, as gigantic as a galaxy. It can be as rigid as rock or as flimsy as flame. No matter what it is, if it's made of matter, then it possesses the power to pull on anything else. Which is an example of a description signal word or phrase in the passage?

What description does that signal word or phrase indicate?