Assertion : Closed circulatory system is less efficient than open circulatory system
Reason : The blood flow is slow is closed circulatory system than in open circulatory system.

Answer: DSolution: The closed circulatory system is more efficient than the open circulatory system because in open circulatory systen, the blood flows through open spaces and channels whereas in closed circulatory system, the blood flows through proper blood vessels. Also in closed circulatory system arterial musculature and precapillary sphincters regulate the flow of blood, so the volume of blood flowing through a tissue or an organ may be regulated according to needs. Moreover in closed circulatory system, the blood flows far more rapidly in closed blood takes much shorter time to circulate through the closed system then in open circulatory system.