Why is an open circulatory system less efficient than a closed circulatory system?

Question

A.  Metabolic wastes cannot be removed from tissues in an open circulatory system.
B.  There is no heart to pump the blood in an open circulatory system.
C.  It is more difficult to quickly deliver O2 to specific tissues when needed with an open circulatory system.
D.  Open circulatory systems lack respiratory pigments that bind to oxygen.
E.  Blood cannot be used to transport nutrients in an open circulatory system.

Clarify Question
What is the key concept addressed by the question?
What type of thinking is required?
 
Gather Content
What do you already know about open circulatory systems? What other information is related to the question?

Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
 
Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
 

Answer 1

C.  It is more difficult to quickly deliver O2 to specific tissues when needed with an open circulatory system.

Clarify Question
What is the key concept addressed by the question?
        · This question is asking about the inefficiency of an open circulatory system.
What type of thinking is required?
        · Apply level:
            o You are being asked to take what you already know and use, or apply, it to the lack of efficiency of an open circulatory system.
 
Gather Content
What do you already know about open circulatory systems? What other information is related to the question?
        · An open circulatory system consists of a beating heart and blood vessels.
        · Rather than entering capillaries, blood in an open circulatory system leaves the vessels and bathes the tissues generally.
        · Blood and the extracellular fluid mix in an open circulatory system, and are together referred to as hemolymph.

Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
        · Open circulatory systems do have hemolymph that has respiratory pigments, so that answer can be dismissed.
        · Some of the functions of blood in any circulatory system, including an open system, is to transport nutrients and to remove waste.
        · A heart is present in an open circulatory system.
        · A characteristic of an open circulatory system that does lead to inefficiency is that blood cannot be delivered to specific tissues; rather it is delivered to sinuses, where it bathes multiple tissues at once.
 
Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        · Apply level:
            o Answering this question correctly depended on your ability to use the characteristics of an open circulatory system in a new situation. If you got an incorrect answer, did you remember that the hart drives theblood into vessels and then into open sinuses, or that the blood is still used for transport and waste removal in open systems? Did you have trouble extending the features of an open circulatory system to determine the correct answer?