| A | B |
|---|
| atmosphere | a mixture of gases that surround a planet |
| air pressure | the measure of the force with which molecules push on a surface |
| altitude | the height of an object above the Earth's surface |
| troposphere | the lowest layer of the Earth's atmosphere |
| stratosphere | the atmospheric layer above the troposphere |
| mesosphere | the coldest layer of the Earth's atmosphere |
| thermospshere | the uppermost layer of the Earth's atmosphere |
| energy | the ability to do work |
| law of conservation of energy | states that energy can be neither created nor destroyed |
| cell | the basic unit of living things |
| stimulus | anything that causes a reaction in a organism |
| solid | the state n which matter takes the shape of its container |
| melting | the change of state from a solid to a liquid |
| freezing | the change of state from a liquid to a solid |
| pressure | the amount of force exerted on a given area |
| renewable resource | natural resources that can be used and replaced over a relatively short time |
| nonrenewable resources | natural resources that cannot be replaced in a short period of time or ever |
| nucleus | holds the cells dna |
