Governmentto rule by right of authority, as a king or queen or elected administrator does: [~ + object]to govern a nation. [no object]I'm sure he governs fairly. to exercise a directing or restraining influence over; control:[~ + object]the motives that govern a decision.
If you mean dispersion it mean splitting light into 7 parts.
They are used to create artificial rainbow effects
The answer is " when you need to make information easier to understand" i have grad point and it said it was correct