Multiple choice Which of the following is not the protein of aqueous layer of the tear film? Lipocalin Lactoferrin Collagen Lysozyme Lacritin Reveal answer Fill a bubble to check yourself C Correct answer Explanation The sclera is a typical fibrous connective tissue containing collagen and elastic fiber. Collagen is a protein that naturally occurs in the body, and is found in cartilage, bones, tendons and skin.