What is the name at structure D?

Which of the following best describes the structure and function of myomeres? 

The gill lamellae are positioned so the water flows though the gills in the opposite direction of the blood, allowing the blood to pull proportionately more oxygen from the water. This mechanism is called? 

The control in the experiment was?  

The gill lamellae are positioned so the water flows though the gills in the opposite direction of the blood, allowing the blood to pull proportionately more oxygen from the water. This mechanism is called? 

Transpiration is caused by ______________. 

Specialized holes in the heart that allow blood to reenter the heart and eventually the anterior and posterior aorta are called

Which of the following is a function of the pereopods? 

When specialized type of cell present on cnidarian tentacles and functions to sting and capture prey? 

What is the name of structure D?