I think its acid fermentation, but I could be wrong. My class studied this a while ago.
the answer is a because if the model is based on experimental data it wont be good unless it has been tested.
They break down the organic matter that has died so that the nutrients stored with in it can be reused.
Vertebrates developed about 550 million years ago. The oldest vertebrate fossils are those of FISH with no jaws. These e<span>arly jawless fish did not have paired fins and their bodies were covered with heavy, bony scaled, but their skeletons were made of cartilage. For the next 50 million years, they were the only vertebrates.</span>
Gametes are an organism's reproductive cells. They are also referred to as sex cells. Female gametes are called ova or egg cells, and male gametes are called sperm. Gametes are haploid cells, and each cell carries only one copy of each