The correct answer is C. The endocrine system helps regulate the nervous system.
Answer: When carbon dioxide binds to hemoglobin, a molecule called carbaminohemoglobin is formed. Binding of carbon dioxide to hemoglobin is reversible. Therefore, when it reaches the lungs, the carbon dioxide can freely dissociate from the hemoglobin and be expelled from the body.
Those symptoms are just common signs of stress. Being too busy or thinking too much in problems can contribute to having those symptoms, which is why it's important to take some breaks.
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i think, its the third one
