Decomposers break down dead organisms and other organic wastes and release inorganic molecules back to the environment. Food chains and food webs are diagrams that represent feeding relationships. They model how energy and matter move through ecosystems
I think the correct answer would be A. The yolk sac becomes the placenta. It is membranous sac that is attached to the embryo. It provides all the nutrition and the blood cells needed by the embryo. It is also called the umbilical vesicle.
I ant see the graph scale
