Answer:
Producers are always at the beginning of a food chain. Producers begin every food chain because they can make their own food.
Answer:
C. Both of the above.........
D.Elements continuously cycle between the physical environment and living organisms.
Ecosystem is encompassing all the life on earth in the physical environment that supports it. An ecosystem involves both the biological (plants, animals, human beings) and non-biological (land, water, soil, and atmosphere) community which interacts as a system. More importantly, the living things are very dependent on the abiotic community since it cannot survive by itself. Every animal, plant and human needs the primary physiological needs of water, food and shelter provided by the abiotic system. <span> </span>