I was recently writing a lab report and noticed that I could reverse the subject and object while still keeping the same meaning.
Shown is a graph of ...
A graph of ... is shown.
I can reverse them in this case, but other times not so much. For example I could say an oak tree is a tree, but a tree is not necessarily an oak tree.
So, my question is in what cases can I reverse the two? And does it depend on if both the subject and the object are nouns or if the object is a adjective, participle, proposition, etc.?