Word "environment" is most commonly used describing "natural" environment and means the sum of all living and non-living things that surround an organism, or group of organisms. Environment includes all elements, factors , and conditions that have some impact on growth and development of certain organism. Environment includes both biotic and abiotic factors that have influence on observed organism. Abiotic factors such as light, temperature, water, atmospheric gases combine with biotic factors (all surrounding living species). Environment often changes after some time and therefore many organisms have ability to adapt to these changes. However tolerance range is not the same with all species and exposure to environmental conditions at the limit of an certain organism's tolerance range represents environmental stress.
Environmentalism is very important political and social movement with goal to protect nature environment by emphasizing importance of nature role in protection of the environment in combination with various actions and policies oriented to nature preservation. Environmentalism is movement connected with environmental scientists and many of their goals. Some of these goals include:
1. to reduce world consumption of fossil fuels
2. to reduce and clean up all sorts of pollution (air, sea, river...) with future goal of zero pollution
3. emphasis on clean, alternative energy sources that have low carbon emissions
4. sustainable use of water, land, and other scarce resources
5. preservation of existing endangered species
6. protection of biodiversity
