单项选择题
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
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
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