x,y,z and t are independent variables in the Navier Stokes equations True False

In Navier stokes equations there are 4 independent variable in which three are positional variables and one time variable.

So the positional variables consist of X,Y and Z and and time variable consists of t.

They all are independent variables because the other variables like temperature, pressure, density and velocity depends on these variables but X,Y,Z and t do not depends on other variables.