Which one of the following animals possesses an open circulatory system:

Explanation

Among the options provided, the animal that possesses an open circulatory system is the Grasshopper. An open circulatory system is a type of circulatory system where the circulating fluid, called hemolymph, is not confined to blood vessels but instead bathes the tissues directly. In this system, the hemolymph is pumped by a simple heart into the body cavity, where it comes into direct contact with the organs and tissues. The fluid then returns to the heart, and the cycle repeats. Now, let's go through the options: Amoeba: Amoebas are unicellular organisms and do not possess a circulatory system. They rely on simple diffusion to exchange gases and nutrients across their cell membranes. Earthworm: Earthworms have a closed circulatory system. However, they have a modified version called a "closed circulatory system with open-ended vessels." In this system, the blood, or more accurately, the coelomic fluid, is contained within vessels, but those vessels are not completely closed. The coelomic fluid flows through the vessels and the body cavity, allowing direct contact with the tissues. Grasshopper: Grasshoppers have an open circulatory system. Their circulatory system consists of a tubular heart that pumps hemolymph into the body cavity, where it directly bathes the organs and tissues. The hemolymph eventually re-enters the heart, and the process continues. Man: Humans, like other mammals, possess a closed circulatory system called the cardiovascular system. The blood is pumped by the heart into a network of blood vessels, including arteries, veins, and capillaries, which deliver oxygen, nutrients, and hormones to the tissues and remove waste products. In summary, the animal from the given options that possesses an open circulatory system is the Grasshopper.