Short answers, pulled from the story.
Skiing has a history of almost five millennia in documented form, but ancient paintings in the Altai Mountains suggest it may have been practiced more than 100 centuries ago. That interpretation of the paintings continues to be debated by historians.
The word ski comes from the Old Norse word "skid", which means a split piece of wood or firewood. Modern skiing evolved from Scandinavian origins, though the practice may have appeared earlier in Central Asia.
Cross-country skiing and ski jumping have both been part of the Winter Olympics since its first edition in 1924. Freestyle skiing was first demonstrated at the 1988 Winter Olympics and was added to the Olympic program in 1992.
The main difference is the ski binding: Alpine skiing uses fixed-heel bindings that attach at both the toe and the heel, while Nordic disciplines use bindings that attach only at the toe, leaving the heel free. Alpine skiing branched off from Nordic skiing around the 1920s when ski lifts made it unnecessary to climb back uphill.
Speed skiing is a discipline in which competitors race for maximum velocity on a straight course. Official records began in 1932 with an 89-mile-per-hour run by Leo Gasperi, and the discipline was demonstrated at the 1992 Winter Olympics in Albertville.
Telemark skiing is a technique and FIS-sanctioned discipline named after the Telemark region of Norway. It uses free-heel bindings similar to Nordic equipment, allowing the heel to lift throughout the turn, but the skis are often as wide as Alpine skis.