The bones that make up our body are alive because if the bones were dead then they would not grow.
When we are born our bones are growing and continue to grow as we go through the baby, toddler, little kid, child, teen and adult ages.
If the bones were dead then our bones would not grow which means that we would not grow bigger and taller.
Bones are very much alive and is one reason the bones when broken are able to heal and repair themselves after you put a cast on the arm, leg etc.
If the bones were dead then the broken bones would not heal.
So yes bones are alive and have the ability to heal and repair.