21. How are levels of economic activities connected to a region's level of development? Be sure to provide examples of primary, secondary, tertiary, and quaternary activities and how they are related to development. (5 points)

The earth's inner core reaches temperatures that are at times greater than 9000°f. what causes this layer to remain solid despite the high temperature?

Which of the following statements is true? a. there is not enough food produced in the world to feed everyone. b. the biggest cause of hunger and malnutrition is the cost of getting food to people who need it most. c. most countries have enough arable land and resources to feed their own population and export a surplus d. malnourishment is only seen in a few countries with very limited food supplies.

According to the earth science reference tables, during which geologic time period were the continents of north america,south america, and africa closest together?