Answer:
Temperature and Light
Sunlight shines through a forest canopy.
Temperature of the air and water affect animals, plants and humans in ecosystems. A rise in temperature has the potential to change the way a living thing develops, because it changes the metabolic rate of the organism. All living organisms have a tolerance level for temperature range. For example, a human being would die if he stood out in minus 50 degree temperatures for any length of time. Light exposure often affects the temperature. Areas with direct sunlight are warmer.
Water
A snow covered forest.
All living organism needs some water intake. Water covers 70 percent of the earth's surface and falls as rain or snow over land. In an environment with little water, only organisms requiring a small percentage of water can survive. Other animals thrive in conditions with large amounts of water, such as marine animals and plants in oceans. Water is essential to survival, but every organism needs a different amount of water.
Atmosphere
Clouds in the sky.
The atmosphere of the earth sustains life. Animals and other creatures breathe oxygen or filter it from water, and plants grow because of the presence of carbon dioxide. Living things combine oxygen and carbon to make carbohydrates, chemicals that provide energy and are important parts of DNA, proteins and other organic materials. The atmosphere is made up of four layers: troposphere, stratosphere, ozonosphere and mesosphere.
