The plesiosaur flipper is convergent with other flipper forms becuase even though they don't share the same evolutionary path, in other words, they don't have a common ancestor with flippers, different animals reached to a simmilar structure with the same function that is locomotion in water.
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The answer is yes. Resistance measurement is used when you switch your multimeter into resistance mode and it is also measured in ohms. It is important to place at the right polarity of the multimeter in order to get the right measurement of your electronic device.
The given blank can be filled with gas exchange.
In the mentioned diagram, the magnified structure shown is of alveoli. Alveoli are an essential component of the respiratory system that functions to exchange the molecules of carbon dioxide and oxygen to and from the bloodstream. These are the tiny-balloon configured air sacs situated at the very terminal of the respiratory tree and are aligned in groups all through the lungs.