What are the exact definitions to the following words?

great wall
han dynasty
immortal
industry
isolated
laborers
legalism
linked
mandate of heaven
military
north china plain
oases
occurs
oracle bones
oxygen
projects
pursue
qin shihuangdi
region
released
revolt
sensor
series
shang dynasty
sibling
silk road
standardized
suspended
trade routes
tributaries
worship
yin and yang
zhou dynasty

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i am not sure use answers.com or dictionary.com

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:

hello there the answer is a

sorry if i am wrong hope that : )