The term “extreme sports”, which we might have seen on a magazine or a website,     1    (be) becoming more and more common as the concept of extreme sports gains     2     (popular). But what are extreme sports on earth?

During the 1970s and 1980s, the term was used for sports with high risks     3     (involve). Today, however, the sports also include activities that give a feeling of adventure without    4    (necessary) putting a participant’s life in danger. For every extreme sport, there is professional equipment that has been developed     5     (protect) your body, improve your performance and give you    6     advantage in the competition.

Extreme sports cover a wide range. Some     7     (develop) from familiar activities so far, like mountain biking, climbing and drag race. Some may not be well known. For instance, bouldering is a kind of rock climbing     8     no rope is used.     9     usually takes place in an area with large rocks or in climbing center.

Nowadays, such sports have become more popular     10     young people all over the world than ever before.