that's not it. Here's
the correct answer ...
5. Which of the following are single-celled microbes called protozoa?
a & b
All of the above
A - Giardia lamblia is a protozoa that lives in water and can
cause diarrhea and cramps. Norwalk, a virus, can also be found
in water and causes vomiting, diarrhea, and abdominal pain. Cholera
(described in the first question) is a bacterium. Virus, bacteria,
and other microbes that can cause illness are called pathogens.
The US EPA requires that water be disinfected at a level that
eliminates 99.9% of waterborne pathogens.
U.S. Food & Drug Administration, Center for Food
Safety & Applied Nutrition, Foodborne Pathogenic Microorganisms
and Natural Toxins Handbook. http://vm.cfsan.fda.gov/~mow/chap34.html
Environmental Health Sciences Center
University of Arizona College of Pharmacy, Room 244
PO Box 210207, Tucson, AZ, USA 85721-0207 firstname.lastname@example.org