Given that our solar system is now about 4.6 billion years old, when will we need to start worrying about the sun running out of hydrogen for fusion?

The african continent is home of the worlds largest desert and longest river . t or f

Since 1980, which three countries have either attacked or been attacked by iraq? a. iran, turkey, united states b. iran, israel, jordan c. iran, kuwait, united states d. iran, saudi arabia, egypt

In what way does renewable energy differ form nonrenewable energy?