e. allows movement in one direction III. Directions: Write the letter of the correct answer on the blanks. 11. What is the thinnest and outermost layer of the skin? a. Sebaceous gland b. Sweat gland c. Epidermis d. Dermis 12. Which of the following is the function of the integumentary system? a. It protects the body against UV rays. c. It serves as the barrier of the body from physical damage. b. It is body's outer covering d. All of the above 13. Which of the following is an accessory organ of the integumentary system is made up of columns of tightly packed dead keratinocytes found all over of the body? a. nails b. hair C. skin d. exocrine glands 14. Which part of the integumentary system is an accessory organ that is made up of sheets of hardened keratinocytes? a. exocrine glands b. skin C. nails d. hair 15. Which part of the integumentary system do the sweat, oil and wax go out? a. skin b. hair C. nails d. exocrine glands​