| A | B |
|---|
| solar energy | energy of sunlight, that is stored as chemical energy in living things |
| chemical bonds | join atoms of carbon to each other and to atoms of other elements |
| hydroelectric energy | electricity generated from the force of falling water |
| tidal energy | one form of hydroelectric energy, that depends on the difference in water height between high tide and low tide |
| biomass | organic matter that can be burned for energy, for example garbage |
| geothermal energy | a source of energy that comes from heat inside Earth |
| nuclear energy | a source of energy that comes from splitting nuclei of atoms |
| fusion energy | a future source of energy, when the nuclei of two small atoms are forced together to form a larger nucleus |
