单项选择题
A．through great social revolution B．through automotive technological revolution C．through numerous mechanical inventions D．through radical political reforms
A．the brain system. B．functions of kidneys C．other human organs related to the kidneys D．reactions of the body to stress and danger
A．the human brain B．glands and systems in the body C．the cortex of the adrenal gland D．the medulla of the adrenal gland