A roller coaster, sometimes known as a roller coaster, is an amusement attraction that features tight bends, steep slopes, and sometimes inversions on an elevated train track. Open vehicles are used to travel along the track, and the rides may be found in amusement parks and theme parks all over the world.

Paper is a thin sheet material made by physically or chemically processing cellulose fibres from wood, rags, grasses, or other vegetable sources in water, then draining the water through fine mesh to leave the fibre equally spread on the surface, pressing, and drying.

Accept obligations of an officer engaged with various fights and conflicts with quick propelling conflict machine. Wage war by walking, driving defensively covered vehicles, or flying a plane. The point of one side might be to assume responsibility for the nation or a district, to accomplish autonomy for an area, or to change government approaches.

The use of chemistry and physics in all elements of photography is referred to as photography science. In order to shoot and develop photographs properly, this applies to the camera, its optics, physical operation of the camera, electronic camera internals, and the process of developing film.