EVERYDAY SCIENCE

Detailed explanation-1: -The circulatory system is effectively a network of cylindrical vessels: the arteries, veins, and capillaries that emanate from a pump, the heart. In all vertebrate organisms, as well as some invertebrates, this is a closed-loop system, in which the blood is not free in a cavity.

Detailed explanation-2: -A closed circulatory system is one in which blood is always contained within vessels. This differs from open circulatory systems in which hemolymph flows into open sinuses surrounding internal organs. All mammals, including humans, have closed circulatory systems. So do all fish, birds, reptiles, and amphibians.

Detailed explanation-3: -All fishes have closed circulatory system. They also possess a two chambered heart that helps in circulation of blood.

Detailed explanation-4: -Similar to the circulatory system in the earthworm, the blood vascular system of the frog is a closed system. It has a lymphatic system similar to humans. The blood vascular system of frogs consists of the heart, blood vessels and lymph nodes.

Detailed explanation-5: -Humans have closed circulatory systems. This means that blood is always enclosed in vessels and the heart while circulating throughout the body. Traveling through arteries and veins, blood carries important molecules throughout the body and is always confined.