Answer:
While humans, as well as other vertebrates, have a closed blood circulatory system (meaning that the blood never leaves the network of arteries, veins and capillaries), some invertebrate groups have an open circulatory system containing a heart but limited blood vessels.
Explanation:
Phytoplanktons are also called microalgae. They are the foundation of the aquatic food web and the primary producers. They feed everything from microscopic to multi-ton whales. Thus, the answer to the question above is letter B. Provide basis of food chains.
