Name two essential components of the tear film and their primary roles in the equine eye.

• A. The aqueous layer provides moisture and antimicrobial factors; the lipid layer reduces tear evaporation and protects the cornea.
• B. The mucin layer provides moisture; the lipid layer is unnecessary.
• C. The aqueous layer decreases evaporation; the lipid layer provides nutrients to the cornea.
• D. Both layers only lubricate and have no antimicrobial roles.

Answer: (A)