Q) Circulatory system is well developed in most of the organism;
a. What is the significance of a circulatory system in organism?
b. What is the difference between open and closed type of circulatory
system?

Dear student , the explanation of (a) . The circulatory system is essential for constant supply of materials like oxygen ,nutrients and other essential substance and simultaneously for the removal of wastes or harmful substances . The explanation of (b) . In open circulatory system ,blood flows through the open sinuses slowly because enough blood pressure is not generated. In open circulatory system there is no red corpuscles. Eg found in arthropods and most mollusks. In closed circulatory system ,blood flows through the closed blood vessels because of it enough blood pressure is generated .In closed circulatory system there is presence of red corpuscles. Eg found in annelids and some mollusks and in human. Thank You and Regards