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.
Allvertebrates have a closed circulatory system, in whichblood circulates away from the heart in arteries andback to the heart in veins. The circulatory system servesa variety of functions, including transportation,regulation, and protection.