A：6
B：7
C：8
D：9
下列各种生理现象中，没有涉及细胞间信息交流的是（ ）
Today is Monday. Linda is at school. She has Chinese，English and PE in the morning. She doesn't have Music today. She has Maths and Art in the afternoon. She has Music on Fridays.
下列物质属于纯净物的是（ ）
