What is the role of protozoa in providing people with milk and meat?

Animal organisms (in particular those producing milk and meat) for the most part eat plant foods containing a large amount of fiber (plant fibers). Animals cannot process fiber on their own. Therefore, in the stomachs of most herbivores there are specific protozoa, which, thanks to their enzymes, are able to break down complex sugar, fiber, into simpler compounds. That is why herbivores are able to give milk as an animal product with a set of animal proteins and meat.