For completeness, just a quick note. The Kelvin scale is not completely "fundamental", in that the "distance " between numbers on the scale is an arbitrary choice. Specifically, the choice that was made is that a one-degree difference in Celcius is the same as a difference of one Kelvin in temperature; i.e. the "size" of a Kelvin is chosen arbitrarily to be the same as the "size" of a Celcius degree (which was originally based on the difference between the melting and boiling temperatures of water at "standard atmospheric pressure" (which is, itself, another approximately arbitrary choice)).

Nevertheless, the Kelvin scale is "more fundamental" than the Celcius scale, since its "absolute zero" is really an absolute - it corresponds to a universal physical property. In comparison, "absolute zero" corresponds to -273.15 degrees Celcius (or is it -273.16? I always forget.)

Farentheit's "zero degrees" was chosen based on the coldest temperature he personally could achieve in the lab with a modicum of effort. His 100 degrees was originally chosen as human body temperature - not quite right, as it turned out.

So, on a scale of relative arbitariness, Farenheit wins the prize for most arbitrary (of the scales still in widespread use*), followed by Celcius, then Kelvin. We can't actually do better than Kelvin, because any choice of the "size" of a degree is always going to be arbitrary. But that's true of *all* physical units that are not dimensionless. Miles and metres are arbitrary. Seconds are arbitrary. Kilograms are arbitrary; pounds are even more arbitrary.

In fact, the only really significant constants in science are the dimensionless ones. Their values are what they are, and we don't get to choose anything about them; nature decides. To understand this is actually to understand something important about science.