1) The development and adoption of renewable energy sources, such as solar and wind power, have contributed to the transition to cleaner and more sustainable energy systems, reducing reliance on fossil fuels and mitigating climate change impacts.

2) The Pacific Ocean is the largest ocean on Earth, covering more than 30% of the planet's surface.

3) The word "school" contains two vowels: O and O.

4) Democracy is a system of government in which power is vested in the people, who exercise it through elected representatives. It allows for political participation, freedom of speech, and protection of individual rights and liberties.