Prepare to Read

Learn Key Vocabulary

Rate and Study the Words Rate how well you know each word. Then:

  • 1. Pronounce the word. Say it aloud several times. Spell it.

  • 2. Study the example.

  • 3. Tell more about the word.

  • 4. Practice it. Make the word your own.

Rating Scale

  • 1 = I have never seen this word before.

  • 2 = I am not sure of the word’s meaning.

  • 3 = I know this word and can teach the word’s meaning to someone else.

Key Words
classified (klas-u-fīd) verb page 340
Photograph of two students writing with plants in front of each student
To be classified means to be arranged or put into groups. Scientists have classified many plants and animals.
Related Word: classify		endangered (en-dān-jurd) adjective page 338
Photograph of an ivory-billed woodpecker
To be endangered means to be at risk of disappearing forever. The ivory-billed woodpecker is an example of an endangered animal.		environment (en-vī-run-ment) noun page 337
Photograph of a woodland with a rocky stream
The environment is all of the living and nonliving things that surround a person, animal, or plant. Every environment affects the things that live in it.
extinct (ik-stingt) adjective page 340
Illustration of a dodo bird
Something that is extinct is no longer living. The dodo bird became extinct because people hunted too many over time.
Related Word: extinction		illegal (i-lē-gul) adjective page 340
Photograph of a “no parking” sign
Something that is illegal is against the law. It is illegal to park in some areas.
Antonyms: legal, lawful		pollution (pul-lü-shun) noun page 338
Photograph of factories with smoke coming from smokestacks
Pollution is waste, chemicals, and gases that have a harmful effect. Air and water pollution hurt living things.
population (pop-yu-lā-shun) noun page 338
Photograph of a crowd of people
Population is the total number of plants or animals in a group. The human population of Earth is more than six billion.		species (spē-shēz) noun page 338
Photograph of a tiger in its habitat
A species is a related group of animals or plants. Lions and tigers are different species. African lions and Asian lions are the same species.		Practice the Words Work with a partner to complete an Expanded Meaning Map for each Key Word.
Expanded Meaning Map

Expanded Meaning Map