What are the major differences between surfing and skiing?

Skiing is carried out on snow or plastic ski slopes and uses to two long thin narrow ski's that a skier would wear on each foot. The skier would have to be wearing ski boots to wear the skis. Skiers would have two poles to help them push themselves on the snow and would also be clothed appropriately for the sport. Surfers use a long wide board that is quite wide and long, the board is able to be laid upon, this could not be done with skis. Surfers would surf on water and attempt to ride waves, this is something a skier could not do. Surfers wear wet suits or shorts and do not normally wear anything on their feet.