8th Grade Science: Fossil Record

The relative age of a rock is

Fossils usually form in

The Triassic, Jurassic, and Cretaceous are

The time it takes for half of the radioactive atoms in a sample of elements to decay is the

The geologic time scale is a record of

When did the atmosphere, oceans, and continents begin to form

Process by which all different kinds of living things have changed over long periods of time

What is G called?

The law of superposition states that, in horizontal rock layers of sedimentary rock, each layer

What Layer is the oldest

Precambrian time, which includes most of Earth's history, began with

What is the age of an intrusion compared to the layers it cuts across

How do most fossils form?

260 million years ago, Earth's continents formed

Law of superposition determines the rocks

A fossil formed when minerals replace all or part of an organism is called a

Paleozoic, Mesozoic, and Cenozoic are all

How long ago did Earth form?

What is a fossil

A type of organism that no longer exist on earth is said to be

What are animals with backbones

Which type of fossil can provide clues about activities of ancient organims