A Natural Balance

The word __________ means "to be arranged or put into groups."

• classified

• pollution

• species

The word __________ means "waste, chemicals, and gases that have a harmful effect."

• pollution

• endangered

• extinct

The word __________ means "the total number of plants and animals in a group."

• population

• environment

• classified

The word __________ means "a related group of animals or plants."

• species

• classified

• population

The word __________ means "at risk of disappearing forever."

• endangered

• illegal

• extinct

The word __________ means "no longer living."

• extinct

• species

• population

The word __________ means "all of the living and nonliving things that surround a person, animal, or plant."

• environment

• population

• classified

The word __________ means "against the law."

• illegal

• extinct

• endangered

Fill in the blank with an adjective that describes the noun. Gray wolves travel _____________________ miles a day to hunt for food.

• many

• strong

• huge

Fill in the blank with an adjective that describes the noun. The jaguar is a _____________________ swimmer.

• strong

• huge

• endangered