Is this true or false hydroelectric power is the least widely used source of renewable energy in the world today?

It is false that hydro is the least widely used. There are many renewable energy sources, and hydro power is one of the most commonly used, with many installations all over the world. Unconventional renewable power sources that have been used include such ideas as extracting energy from the impact of people's feet as they walk on sidewalks, which is just one of many examples of sources less commonly used than hydro.