根据声像图，此为胎儿哪一器官______。
参考答案：肾脏
The dictionary written by Professor Wang is worthy __.
A．of buying
B．buying
C．of being bought
D．to buy
下列物质中，不属于内环境组成成分的是 [ ]
A．载体蛋白
B．甲状腺激素
C．免疫球蛋白
D．葡萄糖
