All dog foods are required to meet certain nutritional standards, so manufacturers must add certain minimum amounts of vitamins and minerals. Like any other ingredients, these can vary in quality and in how well the body can absorb them. Any other supplements are not a "must" but some of them add considerable health benefits. Certain nutrients are lost or altered during processing, but manufacturers of quality foods take great care to add them back into their product after it has cooled down sufficiently. Do not hesitate to ask if you can't locate the information on the bag, in a brochure or on the internet or have additional questions. Trustworthy companies will gladly inform you about their procedures.
“Okay,” I said, wracking my brain. “The truth is, after I finished my essay I took a nap. I had the craziest dream! There were thousands of trees around me, so close that I couldn’t fit through them. I tried to climb over but I was stuck. It was thundering and getting dark. Suddenly I realized the trees had eyes and mouths. They stared at me! The tallest angriest tree said ‘James, you killed my family to write an essay about how living green saves the environment! You’re murdering us one page at a time!’ The other trees wailed and grabbed at me with their branches. It was scary! I woke up screaming! I just can’t use paper Mrs. Cox. If you have to fail me, fail me. But my essay will be just as good if I type it up and turn it in online. Save the trees!” I threw my fist up in the air for effect.