Option 1: The humerus is a long bone located in the upper arm. It connects the shoulder to the elbow and is one of the major bones in the human body.
Option 2: The pericardium is not a bone. It is a double-layered sac that surrounds the heart and helps protect it.
Option 3: The sternum is a flat bone located in the middle of the chest. It connects to the rib bones and forms the front of the ribcage.
Option 4: The tibia is one of the two bones in the lower leg. It is larger and stronger than the fibula and plays a crucial role in weight-bearing and walking.
The correct answer is option 2 - pericardium. The pericardium is a membrane that surrounds the heart, not a bone.