Located in plant cells are large irregular shaped green structures called chloroplasts. They are green because they contain a green pigment called chlorophyll.
An open circulatory system is a type of circulatory system in which nutrients and waste are moved through the body with the assistance of a fluid which flows freely through the body cavity, rather than being contained in veins.
The circulatory system of the blood is seen as having two components, a systemic circulation and a pulmonary circulation. While humans, as well as other vertebrates, have a closed cardiovascular system (meaning that the blood never leaves the network of arteries, veins and capillaries), some invertebrate groups have an open cardiovascular system.