Because it informs us not only of the materials and technical means commonly used during certain periods in history, but can also embody the ideas, beliefs, and aspirations of an era, architecture can be rich in ___.

The answer is "Content".

Explanation:

In a work of art, the material applies to what is portrayed and could seek to draw a fundamental importance. It originated in several different forms that are visual arts, all of which were (realist) or (distorted) figurative. Portraits, landscapes, still life, genre art, and narrative painting are among them, that's why the answer content is correct.