oasis

an underground layer of rock or earth which holds groundwater.

dry.

building filled with equipment and games for gambling.

100 years.

type of fruit tree, including lemon and orange.

group of organisms or objects that share at least one characteristic.

(2,335 kilometers/1,450 miles) river in the western U.S. and Mexico, draining into the Gulf of California.

U.S. land continuously stretching from the Atlantic to Pacific oceans (not including the states of Alaska and Hawaii.)

agricultural produce.

type of fruit tree.

fragile or easily damaged.

the flat, low-lying plain that sometimes forms at the mouth of a river from deposits of sediments.

area of land that receives no more than 25 centimeters (10 inches) of precipitation a year.

construction or preparation of land for housing, industry, or agriculture.

hardworking and consistent.

having to do with money.

able to produce crops or sustain agriculture.

water that is not salty.

industry surrounding games of luck and skill in which players use their own money or goods to have a chance to win more. Also called gambling.

group in a species made up of members that are roughly the same age.

dam on the Colorado River between the U.S. states of Arizona and Nevada. Also called the Boulder Dam.

having to do with more than one country.

to water.

(588 square kilometers/227 square miles) lake formed by the Hoover Dam in the U.S. states of Arizona and Nevada.

corn.

person who sells goods and services.

armed forces.

arid landscape in the U.S. states of California, Arizona, Nevada, and Utah.

(5,592 kilometers/3,473 miles) river in East Africa.

area made fertile by a source of fresh water in an otherwise arid region.

region with a large number of oil wells or other extractive technologies.

outline or border.

constant or lasting forever.

to introduce harmful materials into a natural environment.

amount of precipitation that falls in a specific area during a specific time.

to supply or refill.

large stream of flowing fresh water.

world's largest desert, in north Africa.

small, loose grains of disintegrated rocks.

small flow of water flowing naturally from an underground water source.

buying, selling, or exchanging of goods and services.

path followed by merchants or explorers to exchange goods and services.

huge and spread out.

a hole drilled in the Earth to obtain a liquid or gaseous substance.

movement of air (from a high pressure zone to a low pressure zone) caused by the uneven heating of the Earth by the sun.