What influence does light have in a photograph? when you look at a photograph how does one determine if you have too much light or too little in a photograph?

A Little About Exposure: Exposure is the amount of light a digital camera's sensor captures when a photo is taken. Too much light results in a washed out photo (overexposed). Too little light and the photo will be too dark (underexposed).

What does that mean

Opposition of two melodic ideas is the  right answer