What type of boundary would most likely cause the greatest political problems

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.

While most people who lived in ancient egypt and the middle east avoided settling in nearby deserts, those regions protected them from their enemies. why do you think this was true?

How much water is in the ocean in cubic kilometers