AP BIOLOGY

Detailed explanation-1: -The human body contains trillions of microorganisms-outnumbering human cells by 10 to 1. Because of their small size, however, microorganisms make up only about 1 to 3 percent of the body’s mass (in a 200-pound adult, that’s 2 to 6 pounds of bacteria), but play a vital role in human health.

Detailed explanation-2: -What is the microbiome? In any human body there are around 30 trillion human cells, but our microbiome is an estimated 39 trillion microbial cells including bacteria, viruses and fungi that live on and in us.

Detailed explanation-3: -Most are helpful or at least harmless. The three or so pounds of bacteria living in our gut-mostly in the large intestine-help us digest all manner of food.

Detailed explanation-4: -The skin forms an important barrier against microbes from the outside world. In total, you have about 1.8 m2 of skin, and more than 1.5 trillion (that’s a 1 with 12 zeros) bacteria live on it.

Detailed explanation-5: -About 100 trillion bacteria, both good and bad, live inside your digestive system. Collectively, they’re known as the gut microbiota.