Question

when digging for clams, their primary food, sea otters damage the roots of eelgrass plants growing on the seafloor. near vancouver island in canada, the otter population is large and well - established, yet the eelgrass meadows are healthier than those found elsewhere off canadas coast. to explain this, conservation scientist erin foster and colleagues compared the vancouver island meadows to meadows where otters are absent or were reintroduced only recently. finding that the vancouver island meadows have a more diverse gene pool than the others do, foster hypothesized that damage to eelgrass roots increases the plants rate of sexual reproduction; this, in turn, boosts genetic diversity, which benefits the meadows health overall. which finding, if true, would most directly undermine fosters hypothesis? a) at some sites in the study, eelgrass meadows are found near otter populations that are small and have only recently been reintroduced. b) at several sites not included in the study, there are large, well - established sea otter populations but no eelgrass meadows. c) at several sites not included in the study, eelgrass meadows health correlates negatively with the length of residence and size of otter populations. d) at some sites in the study, the health of plants unrelated to eelgrass correlates negatively with the length of residence and size of otter populations.

Explanation:

Foster's hypothesis is that sea - otter - caused eelgrass root damage increases sexual reproduction, boosts genetic diversity, and benefits meadow health. Option C shows that at sites not in the study, eelgrass meadows' health has a negative correlation with otter populations' residence length and size. This directly goes against the idea that otter - related root damage is beneficial for eelgrass meadows. Option A is about small and recently reintroduced otter populations and doesn't address the core of the hypothesis. Option B just says there are large otter populations with no eelgrass meadows but doesn't show a negative relationship between otters and eelgrass meadow health. Option D is about plants unrelated to eelgrass, so it's not relevant to Foster's eelgrass - related hypothesis.

Answer:

C. At several sites not included in the study, eelgrass meadows' health correlates negatively with the length of residence and size of otter populations.