What is the earth's major external source of energy

Some european explorers sailed west looking for the passage to india

What does it mean to say that "service sector" jobs are predominant in europe's mixed economies today? a. that jobs where people work in factories predominate b. that jobs where people do something for others predominate c. that jobs where people work the land predominate d. that jobs in government predominate

Is when a person has given their consent based on understanding the actions and facts of a study?