The exchange of materials occurs between cells and their environment across the cell membrane.

物质交换穿过细胞膜发生在细胞与其环境之间。

They may be little, but your capillaries are where the big, important exchange of materials actually happens.

它们可能很小，但是你的毛细血管是大规模的、重要的物质交换真正发生的地方。

It was popularized by Edmund Locard, one of the pioneers in the field of forensics, who showed that every time two objects came in contact with each other, there was an exchange of material between them.

它是由法医领域的先驱之一埃德蒙·洛卡尔推广开来的，他指出，每当两个物体相互接触时，它们之间就会发生物质交换。