This is the basic unit of life.
the cell
This layer of Earth is made of solid rock and includes continents and ocean floors.
the crust
The smallest unit of matter.
atom
The change from a solid to a liquid.
melting
This is the chemical symbol for hydrogen.
H
The control center of the cell that contains DNA.
nucleus
The shaking of Earth's surface caused by sudden movement along faults.
earthquakes
A substance made of only one kind of atom.
element
The change from a liquid to a solid is called:.
freezing
The number of protons in the nucleus of an atom. It determines the identity of the element and its position on the periodic table.
atomic number
The maximum number of individuals an environment can support.
carrying capacity
This type of rock forms when heat and pressure change an existing rock.
metamorphic rock
A change that produces a new substance.
A chemical change (or chemical reaction)
The change from a gas to a liquid.
condensation
How much an atom weighs. It counts the particles inside the center of the atom.
atomic mass
In a food chain, these organisms break down dead matter.
decomposers
The process by which water, wind, or ice wear down rocks.
weathering or erosion
This is the starting substance in a chemical reaction.
reactant
The change from a liquid to a gas.
Evaporation (or vaporization)
This element is essential for life and has the atomic number 6.
Carbon (C)
A physical or behavioral trait that helps an organism survive.
adaptation
This supercontinent existed about 300 million years ago.
Pangea
The negatively charged particle that orbits the nucleus.
electron
The change from a gas to a solid.
deposition
This element is a liquid metal at room temperature.
Mercury (Hg)