Concept:Ruminant digestion depends mainly on microbial fermentation in the rumen to break down fibrous feed.
Explanation:Ruminants such as cattle, sheep, and goats have a four-chambered stomach, with the rumen as the largest chamber.
These animals cannot produce enzymes capable of digesting cellulose, which forms the bulk of their fibrous diet.
The rumen hosts billions of microorganisms, including bacteria, protozoa, and fungi.
These microbes carry out fermentation, converting cellulose and other complex carbohydrates into simpler compounds that the animal can absorb.
The fermentation products, mainly volatile fatty acids, serve as the animal's primary energy source.
Enzymatic digestion occurs later in the abomasum and small intestine, but it is not the main mechanism for breaking down roughage.
Mastication only reduces particle size and does not chemically digest fibre.
Since the rumen microbes handle the major breakdown of feed, ruminant digestion is mainly microbial.
Answer:B. microbial