This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
[{'content': 'Which of the following is considered the active form of calcium: \nSelect and explain. \nA. Ionised Calcium, B. Albumin bound Calcium, C. Phosphate bound Calcium, D. Protein bound Calcium', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. IonisedFree iosized calcium is physiologically active form of calciumQ, that is a vital second messenger and is necessary for blood coagulation, muscle contraction and nerve function.Steroid - Glucocoicoids- Mineralocoicoids- Estrogen- Progesteronid derivatives- Derived from tyrosine - Catecholamines- Thyroid hormonePeptide/Protein- ParathormoneQ- Calcitonin- Insulin- Glucagon- Androgen', 'role': 'assistant'}]