Which one is created first? For example if a team worked on a graphical asset of a car, what would be a model and what would be a mesh of the car?
A mesh is part of a model. The mesh defines the vertices of an object. Typically storing them in such an order as to imply their connectivity, like every 3 form a triangle.
Like a mesh of vertices to define the shape of an object.
The model can have other elements like an armature, animation and texture information. It can additionally include more than one mesh. Though, I imagine they're similar enough to be used interchangeably in many cases.
The mesh (as in one single mesh) is just data about the structure of a model. The model contains textures which are used to define how to render it's surfaces. It also contains several variations of the same mesh for animation, normally controlled by bones. Each animation frame could be considered a mesh on it's own.
A very important difference to note is that some models are not built from a mesh in the classic sense of the word. Models structured out of Non-uniform rational basis spline (NURBS) also exit. Technically you could build a model in many ways that do not involve a mesh in the classic sense of the word, such as atoms and Voxels. When people speak of a mesh they normally refer to a polygon mesh.
The mesh is a graph. A collection of vertices, edges and faces. A face is an ordered collection of vertices connected by edges that complete a loop. It is used to describe a flat surface on the mesh.
A model is a general term to describe data. In the specific case of 3d models, we mean the mesh, it's uv-mapping, texture and animations.
A model may not have any texture or animation(if it is not complete or if it's an inanimate object or does not require textures), as long as there is a mesh it will still be referred to as a model. The mesh itself is only the 'wireframe' part of the model. Meaning the collection of edges and their connecting vertices that represent the structure of a model. Unlike a texture which represent how the model is colored, how it reflects light and such things as bump mapping details or it's animation which represent the models motion.
So every mesh is a model on it's own. Not every model is only a mesh.
here are some references:
You may also hear of the term "Solid Model": This means that the underlying mesh model has had such additional information applied, e.g. construction material (and thence can be calculated the model's weight, Centre of Gravity, Centre of Inertia, etc), to the extent that the model is so 'physically' well defined, in a real world sense, that it can be referred to as 'solid'.
In simple terms, a mesh can be regarded as the outline of some shape/object. And the model gives the complete information of that object - texture, reflectivity, color, etc.