We don’t know. Right now, relativity and QM fundamentally disagree on what gravity is. Both are also hugely accurate in their predictions. QM treats it as a force comparable to EM or the strong force. GR says it’s space itself moving. The force we experience is just a reaction to us trying to stay still, as space moves through us.
Beyond that, defining anything as fundamental is a challenge. How are you using fundamental?
We don’t know. Right now, relativity and QM fundamentally disagree on what gravity is. Both are also hugely accurate in their predictions. QM treats it as a force comparable to EM or the strong force. GR says it’s space itself moving. The force we experience is just a reaction to us trying to stay still, as space moves through us.
Beyond that, defining anything as fundamental is a challenge. How are you using fundamental?