What does it mean, if the specific gravity of an object is less than one?

Which phrase describes the paleo-indians of prehistoric arkansas? a. grew cornb. lived in cliff dwellings c. crafted beautiful potteryd. hunted with stone-tipped spearswhich phrase describes native arkansas from the woodland traditiona. developed widespread agricultureb. hunted mastodon and woolly mammothc.built rectangle-shaped homesd. traded salt with other groups