The statements A, C and D is the correct explanation of environment. Key Points Environment is our basic life support system. It provides the air we breath, the water we drink, the food we eat and the land where we live. The place, people, things and nature that surround any living organism is called environment. It is a combination of natural and human made phenomena. The natural environment refers to both biotic and abiotic conditions existing on the earth. Biotic means the world of living organisms. Example - plants and animals. Abiotic means the world of non-living elements. Example - land. Based on the above discussion we can conclude that, the following statements is the correct explanation of environment: A. The place, things and nature that surround any living organism. C. Both biotic and abiotic conditions existing on the earth. D. The combination of natural and human-made phenomena.