Concept:Birds, such as the fowl, have two caeca, while the listed mammals have only one.Explanation:The fowl possesses a pair of caeca located where the small intestine joins the large intestine.These paired structures help in fermenting and digesting fibrous plant material.In contrast, pigs, sheep, and cattle each have a single caecum rather than a pair.Therefore, the animal with a pair of caeca among the options is the fowl.Answer:B. fowl