Why are aerial and satellite imagery used in mapping

If scientists only detect p waves in a certain layer of earths interior what does that tell us?

What type of aid does nigeria receive? short term, tied, voluntary, bilateral, multilateral or long-term?

Which of the following best describes the purpose of a nation’s boundaries? a. to limit the movement of goods and people b. to make it easier for cartographers to create maps c. to make the movement of goods and people easier d. to prevent other countries from invading territory