Name the tough outermost layer of the sac that surrounds the heart.Multiple ChoiceFibrous pericardiumVisceral pericardiumEndocardiumEpicardium

The tough outermost layer of the sac that surrounds the heart is called the Fibrous pericardium.

Explanation

1. Fibrous pericardium: This is the tough, protective outer layer that surrounds the heart and the other components of the pericardial sac. It helps anchor the heart in place while allowing some movement during heartbeats.

2. Visceral pericardium: Also known as the epicardium, this is the inner layer that adheres closely to the heart muscle.

3. Endocardium: This is the inner lining of the heart chambers and valves, providing a smooth surface for blood flow.

4. Epicardium: This is another term for the visceral pericardium, which is directly attached to the heart.

Thus, the correct answer is Fibrous pericardium.