Non Linear Analysis Ansys

When Working on Ansys Non Linear Static Structural Analysis, I couldn't comprehen while defining and assigning material properties to corrosponding bodies.

When I give different random values for density in Engineering Data and runing the jobs parallely the results look SIMILAR for all the independent values, I couldn't fish out on what basis do the software is giving out results.

I have heard that while running static structural analysis and turning on (Large Deflection = On) Ansys doesn't consider the mass properties untill and unless you apply acceleration or gravity, Is it True?

If, Yes, do the software is considering only stiffness as a parameter and calculating all the results internally?

If, Yes, suppose if I am working with an assembly consisting of some 25 parts which are connected either by means of contacts or supports, and if I apply load to either any one of the face (down body) in the assembly by giving specific constraints, do Ansys will consider the weight of all the above parts?      

I will be much obliged, If any one gives me an apt answer in brief.

Respectfully,

Reddy Shyam Shankar.