Work Step by Step
Option a. is incorrect. Blood comes in direct contact with tissues in an open circulatory system. Option c. is incorrect. Blood empties into sinuses in an open circulatory system. Option d. is incorrect. The function of blood, whether in open or closed circulatory systems, is to carry oxygen. Option b. is correct. In closed circulatory systems, blood is pumped through a series of closed blood vessels by a heart.