When something happens, energy is changed from one form into another. When you climb stairs, chemical energy in your food is changed into kinetic energy by your muscles, and into potential energy as you raise your body against gravity. The amount of energy transferred is measured in JOULES.
The tropical rainforest is a biome with a constant temperature and a high rainfall. The level of humidity and density of the vegetation give the ecosystem a unique water and nutrient cycle. Rainforests around the world are threatened by human expansion.
The outer planets<span> are further away, larger and made up mostly of gas. The </span>inner planets<span> (in order of distance from the sun, closest to furthest) are Mercury, Venus, Earth and Mars. After an asteroid belt comes the </span>outer planets<span>, Jupiter, Saturn, Uranus and Neptune.</span>
Carbon dioxide (CO2) makes up the vast majority of greenhouse gasemissions from the sector, but smaller amounts of methane (CH4) and nitrous oxide (N2O) are also emitted. These gases are released during the combustion of fossil fuels, such as coal, oil, and natural gas, to produce electricity.
