Which of the following statements about the diaphragm of a mammal is not correct? it

Step 1: Analyze the question We need the statement that is NOT correct about the mammalian diaphragm.

Step 2: Concept The diaphragm is a dome-shaped sheet of skeletal (striated) muscle below the lungs. It separates the thoracic cavity from the abdominal cavity. When it contracts, it flattens and moves downward, increasing the volume of the thorax. This lowers the pressure in the lungs, so air rushes in (inhalation). It works together with the intercostal muscles.

Step 3: Check each option

• A. Separates the thorax and the abdomen: Correct. This is its position and role.
• B. Is a thick layer of muscle: Correct. It is a muscular sheet with a tendon at its center.
• C. Is made of epithelial cells: Not correct. Epithelial tissue forms linings and coverings, such as the skin, the lining of the gut, and the alveoli. The diaphragm is made of muscle tissue, not epithelial cells.
• D. Is part of the human respiratory apparatus: Correct. It is essential for breathing.

Step 4: Answer The statement that is not correct is C.

Tip: In "which is NOT correct" questions, look for the option that mixes up a tissue type. Remember: diaphragm = muscle = breathing. Epithelium is for lining and covering surfaces.