With unidirectional flow, fish can arrange the blood flow in their gills so that they can extract all the oxygen from the water they inhale. Explain how this is achieved

Can you answer all the parts to this question regarding fish (please type the answer)   Mammals have dead end sacs called “alveoli” and don’t have the super efficient countercurrent exchange system seen in fish. Why do you think countercurrent exchange is necessary for fish? (hint: think about the difference between where most mammals and fish live).

Describe how gas gradients arise; apply them to fish

List at least one reason why arteriole vasoconstriction helps mammals function and survive:

Could you help me with this question? I don't know where to start. All the information has been provided.

What are the pros and cons of closed and open circulatorysystems? Consider not only the type of information in Table 25.2

Discuss the Open and closed circulation in animals