v. to chase and kill wild animals for food
The usually hunt all day and come home at night.

n. a well-organized and developed society
Inca civilization holds many mysteries.

n. one of the seven great land masses on Earth
South America is the fourth-largest continent.

n. an area where something, such as oil or coal, has formed naturally over a period of time in or on the ground
Iron ore is found in the state but the deposits have not been worked on a large scale.

n. a material, such as crystal, coal, salt, etc., that is naturally formed under the ground
Ordinary sand contains different types of minerals.

v. to save or keep something in good condition
Refrigerators preserve food from spoiling.

n. something that comes from nature, is useful, and is bought and sold
The country's most valuable commodities include gold and tin.

adj. always happen; stay the same
The nurses'' attention was constant.

adj. extremely important
Bringing plenty of water is critical, because mountain biking is physically exhausting.

n. a hard flat surface for vehicles, people, and animals to travel on
They walked down the road to the bookstore.