Question

when a stressed out brain communicates with the digestive system it can lead to...
changes in your gut microbiome (bacteria living in your intestines)
heartburn
increased acid in your stomach
all of the above
rewatch

Explanation:

Stress - brain - digestive system interactions can cause various effects. Stress can alter the gut microbiome as the gut - brain axis is disrupted. It can also lead to heartburn and an increase in stomach acid due to changes in the digestive processes triggered by the brain's stress signals.

Answer:

All of the above