Pick from: A. the middle; B. the bottom; C. skin; D. surface;

Answer the following question given this paragraph: Some prokaryotes form structures consisting of many individual cells, like the cells in Figure below . This is called a biofilm. A biofilm is a colony of prokaryotes that is stuck to a surface. The surface might be a rock or a host's tissues. The sticky plaque that collects on your teeth between brushings is a biofilm. It consists of millions of prokaryotic cells. Q: A biofilm is a colony of prokaryotes that is stuck to what? A:
Answer:
D.