Need answers quick Renewable energy: The wave of the future

Which additional piece of information would strengthen the author’s argument that hydroelectric power is the most cost effective source of renewable energy?

The majority of Earth’s surface is covered with water.

People have been utilizing seawater throughout Earth’s history.

Dams built for other purposes can have hydropower added later.

Reservoirs with hydropower can be utilized for recreational purposes.

Based on the article, which renewable energy resource is most likely to be developed for widespread use before other resources?

wind

water

heat

biomass

Based on information in the article, for which renewable energy source does the author provide sufficient evidence that the source could be used in every climate and geographical area of the world?

sunlight

wind

water

geothermal