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.
Find out more about page archiving. Circulatory systems can be open (as in insects) or closed (as in fish and mammals). Closed circulatory systems may be single circulatory systems with a two-chambered heart, or double circulatory systems with a four-chambered heart.