Ideally, a hydrogen fuel-cell vehicle has no environmental impact. Energy is produced by combining hydrogen with oxygen pulled from the atmosphere, and the tailpipe emission is water. The hydrogen fuel could come from a number of sources (Iceland recently started pulling it out of the ground).
A fast shutter speed such as 1/400th of a second will produce a series of crisp frames that have a choppy look when played back. A slow shutter speed such as 1/30th of a second, on the other hand, will produce a series of slightly blurred frames that have a smoother look when played back.
ISO is how sensitive your camera is to light, shutter speed is how long it takes for your camera to take a picture (which in turn alters the amount of light coming in), and aperture is how dilated the lens of your camera is. Not all cameras have this, mostly only digital photography cameras.