Final answer:
Gastrointestinal infections can occur through fecal-oral transmission, with norovirus as an example. 'Equilibrium' is restored by following preventive measures and good hygiene practices.
Step-by-step explanation:
Fecal-oral transmission is a common way in which gastrointestinal infections occur. This happens when pathogens from the feces of an infected person enter the mouth of a new host through contaminated food, water, or hands. For example, norovirus is a viral infection of the gastrointestinal tract that can be transmitted through fecal-oral transmission.
'Equilibrium' is restored by taking preventive measures and following good hygiene and sanitation practices. This includes avoiding and isolating infected individuals, practicing proper handwashing, and ensuring food and water safety.