Match the terms with their definitions.
A prehistoric time when people used stone tools.
Trading goods and services without the exchange of money.
People who have no permanent home and move from place to place to find food, water, and grazing land for their livestock.
The ancient remains of an object made by human beings and discovered during an archaeological excavation.
An animal with two legs or feet.
An animal that eats other animals.
An animal that eats both plants and animals.
An animal that eats grass or plants.
Treeless plains found near the Arctic region of North America, Europe, and Asia that have permanently frozen subsoil.
Very hot and humid regions near the equator.
The gradual process of adapting to one's environment in order to survive.
The external factors that influence the growth and development of people, animals, and plants.
e. natural selection
g. Stone Age