Answer:
Transportation of essential gases an nutrients, waste and unwanted products
Explanation:
the key feature of circulation is transportation of essential gases and nutrients around the body of an organism, removes unwanted products of metabolism from the tissues, and carries these products to specialized excretory organs, if present.
There are many ways that foods can be grouped. The five main food groups are carbohydrates, protein, milk/dairy products, fruits/vegetables, and fats/sugars.