Pumice, obsidian, and scoria are kind of

Scientist believe that earths core is around 6000°c where does this heat come from

Does anyone know the answers for these

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