? That would still be biology and therefore reducible to chemistry and physics.
The approach of “everything is reducible to physics” is actually a philosophical theory that tries to describe what is reality. Is the material world everything that exists? Or are our thoughts (our knowing of things) actually a different reality? Etc.
In the end, the differentiation into the different sciences is simply an aid for people. I wouldn’t pay it that much attention because it really doesn’t tell you anything.