Which of the following describes the endocardium?

a. Intercostal muscles: Intercostal muscles are located between the ribs and help with breathing movements. They don't separate the pleurae.

b. Pleural cavity: The pleural cavity is the space between the pleura and the lung on each side. There isn't another pleural cavity within this space.

c. Mediastinum: The pleura are two thin membranes that line the lungs and inner chest wall. The mediastinum is the central compartment of the thoracic cavity, containing essential structures like the heart, trachea, esophagus, and major blood vessels. It separates the right and left pleural cavities.

d. Diaphragm: The diaphragm is a dome-shaped muscle separating the thoracic cavity from the abdominal cavity. While it plays a role in respiration, it doesn't directly separate the pleurae

a: Producing coagulation factors - This function is associated more with the liver, which produces various clotting factors involved in the coagulation process.

b. Destroying dying red blood cells: The spleen is primarily involved in the destruction of old or damaged red blood cells. It acts as a reservoir for blood, where it filters out old or abnormal red blood cells, recycling their components and removing any potentially harmful substances.

c: Producing leukocytes before birth - Leukocytes (white blood cells) are primarily produced in the bone marrow, not the spleen.

d: Storing glycogen - Glycogen storage is mainly associated with the liver and muscles, not the spleen.