Final answer:
The horse has numerous, small, rod-shaped granules in the eosinophils, which are white blood cells that play a role in the body's immune response, particularly against parasitic worms.
Step-by-step explanation:
The species that has numerous, small, rod-shaped granules in the eosinophils is B) Horse. Eosinophils are a type of white blood cell that contain granules staining best with acidic dyes such as eosin. These granules contain substances like antihistamines and are particularly effective against parasitic worms. Eosinophils are involved in the body's immune response and can increase in number during allergic reactions, parasitic infections, and certain autoimmune diseases. They are easily identifiable by their distinct red-to-orange granules when stained properly.