Research findings have shown that about 20 percent of people only 10 percent can be ____(分类) as “early birds”.
A世界陆地最低点
____
a里海
B世界上最大的咸水湖
b苏必利尔湖
C世界上最深储水量最大的淡水湖
c死海
D世界上最大的淡水湖
d贝加尔湖