Mr. Xu: The arctic squirrel gets so cold while hibernating that its blood temperature falls well below the temperature at which water freezes. Although the squirrel's blood is about 70 percent water, the blood never freezes while the squirrel is hibernating. The squirrel's blood, therefore, must contain a substance that prevents the blood from freezing at the temperature at which water freezes. Ms. Yerky: The blood contains no such substance. Laboratory experiments involving a number of animals, including the arctic squirrel, have shown that a vial of blood from any of the animals freezes at just the same temperature as does a vial of water. 7. Ms. Yerky's response proceeds by A presenting evidence that supports a conclusion inconsistent with Mr. Xu's conclusion B showing that the evidence offered by Mr. Xu was collected by means of unreliable methods C offering an alternative explanation for why the squirrel's blood fails to freeze at the temperature at which water freezes D showing that a key term used by Mr. Xu is ambiguous E showing that the evidence provided by Mr. Xu has no bearing on the point at issue