order of children

Unity Engine
1

What is the order of the children inside a gameobject, is it by child name? It seems a silly question but I am trying to use this code:

for (var i=0;i<transform.childCount;i++)
{

if (i == index)
transform.GetChild(i).gameObject.SetActiveRecursively(true);
else
transform.GetChild(i).gameObject.SetActiveRecursively(false);

}

And I wanted to know what is the sequence of the children to access the proper index number.
Is it possible to change that order?

2

I’m guessing the order of children is undefined (although I don’t know that for sure).