Do SLR camera have zoom?

Yes, SLR's (Single Lens Reflex) cameras have the ability to change lenses from the body to adapt to different photo situations. The benefit is that all functions relating to the photo are functions of the lens. You control the aperture (the amount of light passing through the lens), focus, and zoom from the lens, the only function native to the camera is shutter speed. On automatic SLR's the camera body does all of the light calculations and transmits the information to the lens for you.