Insulin is the correct answer.
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Plasma membrane, Ribosomes, cytoplasm, and DNA.
The answer is <span>Gap Junction
Gap junction is a small gap between the cells that used to transmit signall to the cells. This gap will allow the heart muscle to be activated in unison. Coordinated contractions are important for heart muscle because it creates the force that needed to pump the blood.</span>
They have enough energy to fly because, Birds have a very strong heart and an efficient way of breathing. And, these are necessary for birds to fly. Birds also use a lot of energy while flying and need to eat a lot of food to power their flight.
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