Question 5: the correct answer is Femur. Got it right? Award yourself 1 point.
Question 6 of 10
How many teeth does an adult with a complete set of teeth have?
Why, in question 5: What is the longest bone in the human body?
The answer is the femur, the thigh bone. It is the longest and one of the strongest bones in the body, and it accounts for about a quarter of a person's height. The tibia, in the shin, comes right after it.
Bones that tell stories
Because the femur keeps a proportion to height, archaeologists and forensic experts use its length to estimate how tall a person was from a skeleton.
The femur withstands loads far greater than body weight. When running or jumping, the force passing through it can reach several times the person's weight.
At the top, the head of the femur fits into the hip in a ball-and-socket joint, which allows the leg to rotate in many directions. The shoulder has a similar but even more mobile socket.
Inside the long bones there is marrow. In adults, the central part of these bones stores mainly fat, the yellow marrow, while blood production is concentrated in bones such as the hip, the vertebrae and the sternum.
