In grasslands near the Namib Desert there are "fairy circles" -- large, circular patches that are entirely devoid of vegetation. Since sand termite colonies were found in every fairy circle they investigated, scientists hypothesize that it is the burrowing activities of these termites that cause the circles to form. Which one of the following, if true, most supports the scientists' hypothesis? ['The grasses that grow around fairy circles are able to survive even the harshest and most prolonged droughts in the region.', 'Dying grass plants within newly forming fairy circles are damaged only at the roots.', 'The soil in fairy circles typically has higher water content than the soil in areas immediately outside the circles.', 'Species of animals that feed on sand termites are often found living near fairy circles.']