As a source why might a historian question the reliability of the rig veda as a historical document

A historian might question the rig Veda as a historical document due to the fact that they were said orally.

As oral documents, there may have been some alterations to it and it would be difficult for the historian to know what is true or what is not about the stories.

The rig Veda is an ancient collection of hymns of Indian Sanskrit origin. The Veda are a chant that is said while praising the Hindu god.

It was originally written in the Vedic language but it got to be rewritten in the Sanskrit language. This is one reason why the historian may question its reliability.

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The answer is: it is ancient and written in Sanskrit so things will be lost in translation

The original text of the rig veda has never been found by historians, but they found a couple of reference that was left by past civilizations.

Because of this, there is a pretty good chance that past civilizations also made a couple of mistakes when translating the original text. This make the current interpretation of the document become unreliable.

hygrometers and hair thermometers (often found as part of hygrometers/psychrometers) can be used to measure humidity. barometers are used to measure atmospheric pressure, while anemometers are used to measure wind speed. so the 2nd and 4th choices should be the correct answers.