Any of them. It matters not. Thermodynamic (heat flow from hot object to cold object), statistical (gas expanding to fill a room), cosmological (overall energy distribution of the universe), etc.
Any finite, physical system composed of matter and energy—such as the garden of Eden—must obey the second law of thermodynamics if it's to exhibit coherent causal order and energy flow. Without entropy gradients (differences in potential energy), no work could be done: no photosynthesis, metabolism, or sensory activity. If Eden was warmed by the sun, that's energy moving and thus entropy. If Eden had green plants, that's photosynthesis and thus entropy. If Adam and Eve could eat food, that's digestion and thus entropy.
And so on.
If there were no entropy in Eden, there would be no life in Eden. The Fall introduced moral disorder, not physical laws.