Meaning of porque nos alimentamos de productos que provienen de otros seres vivos y no de arena

porque nos alimentamos de productos que provienen de otros seres vivos y no de arena: Because we are not autotrophic organisms, i.e., can do photosynthesis which transforms inorganic substances in organic by the energy of the light ( vegetables and algae ) Neither the chemosynthesis which transforms them by the energy released in 40 oxidation; fungi and some bacteria ). We are heterotrophic and need the autotrophs to make us food ( carbohydrates, fats and proteins ). Also we can absorb mineral salts and trace elements dissolved in water through the digestive system.; Animal origin products provide us with proteins, if you eat sand you die; Because we are not autotrophic organisms, i.e., can do photosynthesis which transforms inorganic substances in organic by the energy of the light ( vegetables and algae ) Neither the chemosynthesis which transforms them by the energy released in 40 oxidation; fungi and some bacteria ). We are heterotrophic and need the autotrophs to make us food ( carbohydrates, fats and proteins ). Also we can absorb mineral salts and trace elements dissolved in water through the digestive system.