Đang chuẩn bị liên kết để tải về tài liệu:
Chapter 2: Bacteria and Water Quality
Đang chuẩn bị nút TẢI XUỐNG, xin hãy chờ
Tải xuống
Bacteria are microscopic, single-celled organisms that are the most numerous organisms on earth. They are so small that over five million could be placed on the head of a pin. Bacteria can live in numerous environments and perform many complex actions, some of which are beneficial and some harmful. Most bacteria, however, are not harmful and do not cause human health problems. Those that are disease producing are referred to as pathogenic. Viruses and some protozoans can also be pathogenic.