a fossil of a type of organism that lived in many places during a relatively short time span

the layer of Earth extending from Earth's center to the bottom of the mantle. It is mostly metallic iron and nickel

a personal belief or judgment based on what a person thinks or feels but not necessarily based on evidence

an investigation in which all the conditions are controlled to test a hypothesis

forces that cancel each other out because they are equal in size and opposite in direction

a break in Earth's crust where rock on one side moves in relation to rock on the other side

a product of technology used to benefit organisms and the environment

a continuous flow of water in a regular pattern in the ocean

the process of moving sediment from one place to another

the bouncing of light waves when they encounter an obstacle