Why do you think it is functionally important that the bones of the os coxae fuse together rather than remain independent bones

Provides more strength.

Explanation:

It is functionally important that the bones of the os coxae fuse together rather than remain independent bones because the fusion of bones of the os coxae increases their strength and they can perform their function very well. If the fusion of bones of the os coxae did not occur and they remain independently so they can't bear the load of the body and so the function is also adversely affected.

i don't know. the other person does though.