What organs and organ systems appeared in multicellular animals?

In the course of evolution, multicellular animals received various organs that are connected into organ systems. Let’s take the example of man, since we have all the organ systems of multicellular animals. It is the nervous system that regulates all the processes of the body. The musculoskeletal system is needed for movement. The digestive system is necessary for the breakdown of food into proteins, fats, carbohydrates, vitamins, and more. The excretory system is needed to remove processed substances from the body. There is also the respiratory, circulatory, endocrine and reproductive systems.