History textbooks are completely objective and do not reflect a biased interpretation of history.

The statement is - False.

History textbooks, more often than not, are not interpreted objectively and very often the perspective and interests of the nation were a certain history textbook is out for the wider public is subjective and with nationalistic elements. This is the case in most of the countries in the world and there's countless number of examples of it, like:

The Republic of Macedonia is claiming the Macedonia region in Greece as its own ethnic and historic territory and that Alexander the Great is Macedonian, and even though it was ethnic territory of the Macedonians till recently, a Macedonian state was not existent and ruling over the region for approximately two millenniums. Greece on the other hand claims the Macedonia region as its own historic region and ALexander the Great is Greek, even though the Greeks never managed to take that region under their control until the early 20th century. Bulgarians claim that the Republic of Macedonia is their own territory as the Macedonia region in Greece as well, and considers the people in this part to be Bulgarians and that Alexander the Great is Bulgarian. That's just one simple example, and there's lots and lots around the world.

i think its toxic gasses but i could be wrong