Metaphorically, a branch is used to mean a division. Let us say, for example, that we are talking about the art of cooking. We might assert that they are two main branches of cooking, the French and the Italian (actually there are more than two, but perhaps I am a French-Italian snob and I believe that only those two types matter).
The main branches of science mean that there are main areas of science. These areas include biology, chemistry, and physics.
The 4 main branches are:Janus, Tomas, Ekaterina, and my favorite which are the Lucian. Another known branch but is not 'main' are the Madrigals,
gave me cot code of khnawal main baranch
when science branches overlap that means that they are overfilled with to much information
Experimental and Theoretical, probably