Are microorganisms friend or foe?
• United States
12 Jan 08
They can be both, depending on the microorganism. Some are harmful or fatal to humans, and others are essential to life--like the ones that live in the digestive system and make the breakdown and digestion of food possible. There are of course many dangerous ones, like some strains of E. coli or cryptosporidium of staphylococcus.