What new point does sagan make with the historical evidence he discusses here ?

What is the main idea of this paragraph

What theme is best revealed by this conflict? a.)with cooperation, crews can defeat the gods. b.)dangerous ocean travel claims many lives. c.)rest is required for all who work hard. d.)people must respect the wrath of the gods. read the excerpt from part 1 of the odyssey. now zeus the lord of cloud roused in the north a storm against the ships and driving veils of the squall moved down like night on land and sea. the bows went plunging at the gust; sails cracked and lashed outstrips in the big wind. we saw death in that fury, dropped the yards, unshipped the oars, and pulled for the nearest lee: then two long days and nights we lay offshore.

Those are books that need to be returned to the library what is the antecedent of the pronoun those