Organisms and their environments are dynamic and interdependent. The term ‘ environment’ etymologically means surroundings. It includes everything (biotic as well as abiotic) that surrounds an organism. Any factor, abiotic or biotic, that influences living organisms is called environmental factor (or ecological factor or ecofactor). Abiotic factors include factors such as temperature, sunlight levels, pH, salinity and soil composition. In contrast, biotic factors encompass producers, consumers and decomposers.