Complete question: Serous fluid secreted by both the parietal and visceral layers of the pericardium, and released into the pericardial cavity, lubricates the membranes and facilitates the almost frictionless movement of the heart when it beats. True or False.
Answer: True
Explanation: The enclosed space between the parietal and visceral layers of the pericardium is known as the pericardial cavity. It contains the serous fluid (secreted by both the parietal and visceral layers of the pericardium), helps in lubricating surface of the membrane and allows the heart to move easily.