Write one or two words for each of the following statements/definitions : (a) Each level of the food chain where the transfer of energy takes place (b) The physical factors like temperature, rainfall, light soil air and water of an ecosystem (c) Organisms which depend on the producers for food either directly or indirectly (d) The physical and biological world where we live in (e) Self-contained unit of living things and their non-living environment needing only sunlight for its functioning