When ___in arctic regions, the Aleuts construct igloos as temporary winter shelters.

Most substances contract when they freeze so that the density of a substance’s solid is ___of its liquid.

The mechanism by which brain cells store memories is ___clearly understood.

Desert animals ___a means of retaining moisture in such a hot, dry climate if they are to survive.

___state of Wyoming is also known as the "Equality State" because Wyoming women were the first in the nation to vote.

Fructose is a monosaccharide sugar that is much sweeter ___.

Ground plans and contour maps of the Earth ___from aerial photographs.

By the middle of the twentieth century, painters and sculptors in the United States had begun to exert ___over art.

___millions of galaxies exist in the vast space outside the Milky Way.

The extent of the harmful effect of locoweeds on animals depends on the soil ___the plants grow.