Which statement about the diaphragm is correct?

The diaphragm plays a crucial role in the respiratory system by separating the thoracic cavity from the abdominal cavity. This anatomical feature is essential because it allows the lungs to expand and contract during breathing while also providing a barrier between the organs in the two cavities. When the diaphragm contracts, it moves downwards, increasing the volume of the thoracic cavity and decreasing the pressure within, which draws air into the lungs. Conversely, when it relaxes, it moves back up, helping to expel air from the lungs. This separation is also significant for protecting the abdominal organs and aiding in intra-abdominal pressure management during activities such as lifting and bending.

Thus, the statement regarding its role in separating the thoracic and abdominal cavities is accurate and highlights the diaphragm's essential function in both anatomy and physiology related to respiration.