Which of the following crops are grown in the tierra caliente elevation zone?
a. wheat, beans, and potatoes
b. barley, oats, and rye
c. coffee, corn, and wheat
d. sugarcane, bananas, and cacao

Dubai is challenged by all of the following environmental factors except a. a warm and dry climate b. a lack of annual rainfall c. scarce freshwater resources d. a lack of valuable natural resources