Question

An open circulatory system is found in __________, where the coelomic cavity is filled with blood.
A) Arthropods
B) Mammals
C) Aves
D) Reptiles

Answer 1

Hint:-Most multicellular organisms have a functioning circulatory system. The circulatory system enables the flow of nutrients, oxygen, and other important components throughout the body. Not just that, a properly functioning circulatory system helps maintain a body’s pH and temperature. The circulatory system can be divided into an open circulatory system and a closed circulatory system.

Complete step-by-step solution:-
Arthropods fall into the invertebrates category; they are characterized by features such as the presence of an exoskeleton, having a segmented body, etc. Arthropods have an open circulatory system. They do not have vessels that help circulate blood. Instead, the blood is circulated within the body cavity known as hemocoel. The blood is called hemolymph as its blood mixed with interstitial fluid. The blood enters the heart via an open called ostium. The heart pumps the blood into the body cavity; all the organs within the body cavity receive their nutrients.
Mammals are vertebrates and they have a closed circulatory system. Here blood has no direct contact with the organs. Blood vessels i.e. the capillaries veins and arteries carry the blood to various organs and back. A mammalian heart has four chambers- two auricles and two ventricles.
Aves like mammals have a closed circulatory system. Their circulatory system is quite similar to that of mammals. They also have four chambers that are involved in blood transport throughout the body. Reptiles also have a closed circulatory system. However, most reptiles have 3 chambers in their heart- two auricles and one large ventricle.
The correct option is (A). Arthropods have an open circulatory system.

Note:- Certain organisms have no circulatory system like in the case of flatworms. Their digestive systems and muscle pharynx help in the transport of nutrients. Reptiles, mammals, and birds have both pulmonary circulation (blood is transported from the lungs to the heart and back) and system circulation (flow of blood throughout the body). Compared to an open circulatory system, a closed one exerts more energy to function as a whole.