you have some facts wrong. the nicoabri are of malay origin. they are coastal people and are the most assimilated of the tribes. they live in the nicobars. the shompen are also malay origin, but are still hunter-gatherers and live inland on Great Nicobar. The four negrito tribes are in teh Andaman. the Great Andamanese are demographically extinct. the Onge are on their way. Jara are still on the safe side of teh fence. Sentinelese are the safest on their own island. It is the Sentinelese that fired arrows. yes we preseume they are safe based on stories conveyed from the Onge and Great Andamanese.
your statement in the second paragraph is not clear so I shall leave it at that.
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