Explain the causes and effects of international and internal migration patterns over time.

**This is an essay question for a grade, please help! I've been studying for 3 hours and sitll have no idea :(**

the answer is

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:

imma have to go   the third option

sorry if i am wrong hope this

if i am right plz give me brainliest