The average human digestive tract is home to as many as 1,000 species of microorganisms.

Despite all this, scholars remain divided as to how 'special' the human vocal tract really is.

The normal human digestive tract contains about 400 types of beneficial bacteria.

Five years later, Darwin had been replaced by a drawing of the human digestive tract.

The human genital tract is the only reservoir for this species.

Little is known about this type of pollution from cars and how it damages the human respiratory tract.

Methanosarcina have even been found in the human digestive tract too.

The bacterium is naturally present in the human digestive tract at 3-5%, but has been seen to fall with obesity.

The gel would pass completely through the human digestive tract without dissolving.

Both bacteria generally live in the soil and human intestinal tracts.