Q: These microorganisms are abundant in the human digestive track and serve many roles.  what are they?


Read this paragraph and choose the correct option from the provided answers:

Bacteria provide vital ecosystem services. They are important decomposers. They are also needed for the carbon and nitrogen cycles. There are billions of bacteria inside the human intestines. They help digest food, make vitamins, and play other important roles. Humans also use bacteria in many other ways, including:.

 Choices:

- antioxidants

- pathogens

- tumors

- bacteria


A:
bacteria