| A | B |
|---|
| matter | anything that has mass and takes up space |
| atom | the smallest unit of a substance that maintains the properties of that substance |
| element | the most basic substances on Earth |
| compound | when atoms are combined |
| molecule | two or more atoms held together by chemical bonds |
| energy | the ability to cause change |
| producer | an organism that uses energy and matter from the environment to make its own food |
| consumer | an organism that gets energy and matter by eating other organisms |
| decomposer | an organism that gets energy and matter by breaking down the remains of organisms that had died |
| chemical reaction | a process in which atoms are rearranged to produce new substances |
| reactants | the starting substance in a chemical reaction |
| products | the substances formed in a chemical reaction |
| photosynthesis | a chemical reaction in which the cells of producers use energy from the sun to make sugar |
| biofuels | fuels that are produced from plant or animal matter |
| fossil fuels | fuels made from decomposed plants and animals that have been buried in the ground of millions of years |
| cellular respiration | a process that uses oxygen to release the energy stored in food molecules |
| food chain | the pathway that energy and nutrients follow through an ecosystem |
| food web | a model that shows how energy flows between organisms in an ecosystem |
| energy pyramid | a representation of the energy available at each level of a food web |
| fermentation | a process in which organisms release energy from sugars |
| Water Cycle | the continuous movement of water through Earth's ecosystems |
