Informational Vocabulary
Grade 3 Reading Worksheet

Circle the answer.
Read this first
Clues in the Rocks
Long ago, animals and plants lived in places that look very different today. How do we know? Scientists study fossils, or the hardened traces of plants and animals from long ago. A fossil can be a bone, a shell, or even a footprint left in mud.
Most living things never become fossils. A fossil forms only when something is buried quickly. Mud or sand covers a shell on the floor of a sea. Over many years, more layers pile on top. The layers press down and slowly turn into rock. The shell is preserved, or kept safe from rotting, inside the stone.
Sometimes the shell itself wears away. Then only its shape is left behind. This kind of fossil is called an imprint. An imprint is like the mark your shoe makes in wet sand.
Scientists who study fossils are called paleontologists. They dig with small tools, such as brushes, picks, and spoons. They work slowly so they will not crack a fragile bone. A fragile thing breaks easily, unlike a strong rock.
Fossils tell us about animals that are now extinct. Extinct animals are gone forever, and none are living anywhere today. Mammoths are one example. Fossils also show that some deserts were once covered by warm seas. Ancient shells, from millions of years ago, have been found on dry land far from any ocean.
In paragraph 1, what are 'fossils'?
- rocks that form at the bottom of a sea
- tools scientists use to dig in the mud
- traces of plants and animals from long ago
- bones of animals that are living today
In paragraph 2, what does 'preserved' mean?
- kept safe from rotting
- dug up by scientists
- washed away by water
- broken into small bits
Which phrase from the text is the best clue for 'imprint'?
- more layers pile on top
- kept safe from rotting
- the mark your shoe makes in wet sand
- buried quickly
In paragraph 4, scientists dig with 'picks.' What are picks here?
- choices a person makes
- bones found in rock
- small digging tools
- maps of where to dig
In paragraph 4, what does 'fragile' mean?
- hard as stone
- found underground
- breaks easily
- very old
Which phrase shows a contrast clue for 'fragile'?
- work slowly
- unlike a strong rock
- Mammoths are one example
- dig with small tools
In paragraph 5, what does 'extinct' mean?
- gone, with none living today
- very large and heavy
- living only in warm seas
- hidden deep under rock
Which word from the text means from a very long time ago?
- extinct
- fragile
- preserved
- ancient
What is a 'paleontologist'?
- a scientist who studies the stars
- a worker who sells shells
- a guide who leads ocean trips
- a scientist who studies fossils
In paragraph 2, a shell lies on the 'floor' of a sea. What does 'floor' mean here?
- the bottom of the sea
- the top of the water
- one level of a tall building
- the part of a room you walk on


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