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.
More in High Blood Pressure. The circulatory system, also known as the cardiovascular system, is a simple loop which starts, and ends, with your heart. It is a closed system, meaning blood does not enter or leave the system during its journey from your heart to your body and back again. In such a system, a continuous flow of the same liquid can be pumped through the loop again and again.