Answer: D) The kidneys deactivate vitamin D and stimulate the activity of osteoclasts Explanation: The kidneys deactivate vitamin D and stimulate the activity of osteoclasts is wrong among the functions of kidneys.   The kidneys are two bean-shaped organs in the renal system. They help the body pass waste as urine. They also help filter blood before sending it back to the heart.   The kidneys perform many crucial functions, including: maintaining overall fluid balance. regulating and filtering minerals from the blood. filtering waste materials from food, medications, and toxic substances. creating hormones that help produce red blood cells, promote bone health, and regulate blood pressure.

Answer: C) two Explanation: Clearly, we may mark such sets of 3 numbers, in which the middle number is 8 and each of the two numbers on both sides of it is a factor of 8, as shown below : 2 8 3 8 2 4 8 2 4 8 6 8 2 8 2 4 8 3 8 2 8 6 So, there are two such 8's. Hence the answer is C.