What is absent in aqueous humor?
(a)Carbon dioxide
(b)Oxygen
(c)Hyaluronic acid
(d)Glucose

Hint: The fluid helps to retain over 1000 times its weight in water within the cells of the skin as well as in delivering nutrients. This fluid also involves many signaling pathways including those involved in embryonic development, wound healing, inflammation, and cancer.

Complete answer:
Aqueous humor is the thin, watery fluid that fills the space between the cornea and iris which is continually produced by the ciliary body, the part of the eye that lies just behind the iris. The watery fluid nourishes the cornea and the lens and gives the front of the eye its form and shape. The composition of aqueous humor is-
Water, Ions like- bicarbonate, buffers metabolic acid, chloride ions, preserves electric neutrality
Protein like- albumin, beta globulin, Ascorbate, Glucose, Lactate produced by metabolism of the anaerobic structure of the eye, Amino acids

Additional Information: -The trade name of hyaluronic acid is Hyaluronan and Restylane which is a viscous fluid carbohydrate present in connective tissue, synovial fluid, and vitreous humor of the eyes.
-Hyaluronic acid is a mucopolysaccharide that is composed of alternating residues of the monosaccharides glucuronic acid and glucosamine joined together by beta- 1,3 and beta which can form a hydrogen bond with water molecules.
-Source of hyaluronic acid are- foods like rooster comb, beans, capsules, cream, serum, spray, injection, etc.

So, the correct answer is, ‘hyaluronic acid.’

Note: -Hyaluronic acid decreases by aging therefore wrinkles and folds are formed.
-Hyaluronic acid is injected into joints to treat patients suffering from knee osteoarthritis, periarthritis of the shoulder, and knee pain for rheumatoid arthritis.