When did the appalachian mountains form?

When a dam is built in a hot, dry area, creating a lake or reservoir aboved the dam, how does the evaporation from that reservoir affect the environment ?

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.

What two advantages do the coastal countries of west africa have over the sahel countriesfertile soil and mineral resources temperatures and terrain human resources and natural resources weather patterns and location