What do Franz Gall, Charles Darwin, and Sir Francis Galton all have in common? They all promoted the idea of “survival of the fittest.”
They all believed that “book” smarts is the most important type of intelligence
They all believed that intelligence had some kind of biological basis.
They all developed tests for intelligence that we still use today.

option d is correct. corroborated sources of historical evidence   is necessary to validate a claim about an event in history.

historians tend to use written sources, but audio and visual materials as well as artifacts are important objects that supply information to modern historians.

historical sources are usually divided into two categories: primary and secondary sources. depending on the historian's intent, some sources shift their designation. determining what type of sources toimplement, and the level of credibility and reliability of those sources, is a significant step in critical thinking for the historian.

explanation:

the answer should be monarchy