In science nothing can be called fundamental. This is why ex nihilo creation is popular in physics, such that 'Nothing' can be called fundamental. Time and space are not fundamental, or not provably so, so no time-bound extended phenomenon of the type science deals with can be fundamental.
This is the reason why metaphysics exists, so that physics does not have to worry about fundamental questions and can get on with examining appearances. The phrase 'fundamental physics' is deceptive. It will never be fundamental until it incorporates ontology and metaphysics.
Hence time and space are considered explanda for metaphysics, not for physics, leaving physics as non-reductive. This is as it should be. There is much confusion on this point but most dictionaries will clearly place space-time in metaphysics, meaning that only in metaphysics do we deal with fundamental questions.