To swim in the olympics, you have to be selected for your country's olympic team, which will typically be selected in the year leading up to the competition. Selection usually occurs at a national qualifying event, which you must achieve a qualifying standard to enter. In some countries the qualifying standard for the event must be met at a certain level of competition. Usually up to two atheletes will be selected for each olympic swimming event, but some teams will choose not to enter an event if they do not feel that they can compete seriously with the representatives from other countries.
The one with potebtial can compete
204 Countries participated in the 2008 Beijing Summer Olympic games.
India, I think
He placed well enough in a regional Olympic qualifying event to be given the opportunity to compete in the Olympic Games themselves.
There are a lot of countries that compete in the wrestling Olympics the bigger countries in the sport are Russia the United States
Different sports have different qualifying procedures. Track and field athletes compete for the olympic team through qualifying tournaments or their national rankings.