单项选择题
A．The adrenal gland is located on top of the kidney. B．Each kidney is composed of two adrenal glands. C．The medulla is inside the cortex. D．The cortex and the medulla have different functions.
A．a scientist as well as a naturalist B．a naturalist but not a scientist C．no more than a born naturalist D．first of all a scientist
A．he didn't live very long with them B．the family was extremely large C．he was too young when he lived with them D．he was fully occupied with observing natur