Explain manifest destiny. What was it? Where did the idea come from? What did it mean for the people in the east? What did it mean for the people and animals in the west? Why is it so important?

President of the united states has scheduled a cabinet meeting today to discuss energy policy with specific focus on pollution and global warming. given what you know of the executive branch, which group of attendees would the president most likely expect to provide up-to-date information and expert insight during this meeting?