The question before a jury isn’t, “what was the cause of death?”
There was enough evidence that somebody killed Caylee. There was enough evidence that that somebody had to be Casey. A scientific determination of the exact means of death is not a required component.
This jury is the worse. However, they come from the same community that thought Terri Schiavo should have no water or other nourishment. I guess in their minds it was a late abortion and Casey should have the right to be free from motherhood.