Joanie brought home several different seashells from the beach. Which one is a fossil?

• a clam that died on the way home

• a rock with an imprint of a seashell

• a clump of seashells stuck together

• two seashell halves that fit together

What causes petrified wood to form?

• Cells of wood are slowly filled with minerals.

• Sediment hardens around a piece of wood.

• A piece of wood is frozen for thousands of years.

• A piece of wood becomes trapped in tree sap.

Which part of an organism is the most likely to be fossilized?

• the feet

• the hard tissues

• the head

• the soft tissues

What is a scientist who studies fossils called?

• a biologist

• a botanist

• a paleontologist

• a physicist

Fish live in many different environments such as lakes, ponds, and oceans. Which is one feature in fish that has changed greatly over time?

• scales

• bones

• eyes

• jaws

At a family reunion, people are talking about everyone’s age. The family members all line up without saying anyone’s exact age. What principle is the family using?

• absolute age

• relative age

• estimate age

• approximate age

Sharon is studying some rock layers near her home. She uses the terms Precambrian, Paleozoic, Mesozoic, and Cenozoic to name them in order of their age. What are all these terms part of?

• the world calendar

• Earth's history

• the geologic time scale

• the fossil record

Scientists know that the continents have moved across Earth's surface throughout history. What is the name of the idea that first described the movement of continents?

• plate tectonics

• continental drift

• continent movement

• landform change

Scientists use fossils to describe how all of the environments on Earth have changed over time. Which fossil discovery represents a change in the environment where the fossil was found?

• fish in rocks on top of a mountain

• seashells in the sand at the beach

• horse bones in soil in the prairie

• polar bear bones in Alaska

Many fossils found today are from plants and animals that no longer live on Earth. Sometimes this is due to a large number species dying out over a relatively short time. What do scientists call this type of dying out?

• great due-off

• species death

• mass extinction

• population change