What role does microbial action play in the diet of ruminants?

Microbial action is a critical component of the digestive process in ruminants, such as cows and sheep. These animals have a specialized stomach with multiple compartments, including the rumen, which hosts a vast population of microbes. These microbes are essential for breaking down complex plant materials, particularly cellulose, which is difficult for the animal to digest on its own. Through fermentation, these microorganisms convert cellulose and other carbohydrates into volatile fatty acids, which serve as a primary energy source for the ruminants. This symbiotic relationship allows ruminants to efficiently extract nutrients from plant-based foods, making option B the correct choice.

The other options do not accurately describe the role of microbial action in ruminant diets. Eliminating the need for plant material overlooks the fundamental dietary requirements of these animals. Stating that microbial action ensures ruminants require less food is misleading; rather, it enables them to utilize the food they consume more effectively. Additionally, microbial action enhances rather than limits digestive efficiency, facilitating the breakdown of fibrous materials that ruminants could not access otherwise.