Life Science Final Practice Exam

Why does the adult human skeleton have fewer bones than an infant's skeleton?

Because bones grow larger but not more numerous Because bones fuse together during growth Because bones disappear Because bones become cartilage

Correct Answer:

Because bones fuse together during growth

Explanation:

The main idea is that the number of bones changes as we grow because some bones fuse together during development. Infants start with about 270 bones, and as growth proceeds, several bones join to form single bones—especially in the skull, where sutures fuse, and in other parts like the pelvis and spine—so the total count decreases to around 206 in an adult. Bones do grow in size, but that growth doesn’t explain the reduced number as much as fusion does. They don’t disappear, and while cartilage is involved in forming bones (endochondral ossification) and that cartilage remains at joints, bones don’t simply turn into cartilage as a normal part of aging.

Access more questions from this quiz

Continue to Life Science Final Practice Exam for more practice questions and the full quiz experience.

Access More Questions