Macromolecules not digested, but present in duodenum?

When we eat, the food that we swallow needs to be digested or broken down into nutrients that our bodies are able to absorb. Complex protein and sugar molecules need to be broken down into macromolecules. The duodenum is also known as the smallest and shortest segment of the small intestine. Digestive enzymes are macromolecules that are not digested, but present in the duodenum. Their sole function is to help break down the food into smaller molecules allowing the nutrients to be extracted and absorbed through the wall of the duodenum into the rest of the human body

Explanation:

Bacteria grow to a fixed size and then reproduce through binary fission which a form of asexual reproduction. Under optimal conditions, bacteria can grow and divide extremely rapidly. Different kinds of bacteria need different amounts of oxygen to survive. that's all I know sorry :(