Question

duckweed is a small freshwater plant that is often exposed to zinc pollution. sofia vámos and colleagues collected samples of four duckweed ecotypes (genetically and geographically distinct populations within a species), along with water from each ecotypes habitat. hypothesizing that each ecotype is adapted to its local conditions in ways that bolster its growth and resistance to pollutants, the researchers grew each ecotype in all four water samples and with three levels of zinc (none, low, high). (the researchers did not replicate local differences in light or temperature.) they found that the ecotypes grew equally well in all four water samples and that adding zinc consistently enhanced growth, regardless of concentration, suggesting that____. which choice most logically completes the text? a. if each ecotype is indeed locally adapted as the researchers hypothesized, those adaptations are to other environmental conditions than the water each ecotype inhabits. b. while the ecotypes are genetically and geographically distinct, those differences do not represent adaptations to local environmental conditions. c. there may not be significant differences in the water that each ecotype inhabits, but there are significant differences in each ecotypes resistance to zinc pollution. d. although the researchers hypothesis does not appear to be supported, this may be because the levels of zinc exposure the plants in the experiment received did not match their exposure in their natural environments

Explanation:

The text is about duckweed ecotypes and their adaptation to local conditions. The key is to find the option that logically completes the text based on the research findings. Option A is correct because if each ecotype is locally adapted (as hypothesized), then they should be adapted to their local environment more than to others. Option B is wrong as the text implies they are genetically distinct. Option C is incorrect as the research is about adaptation to local conditions (including zinc as a pollutant). Option D is not supported as the experiment's non - matching exposure doesn't refute the hypothesis of local adaptation (the hypothesis is about local adaptation in general, not just zinc exposure in the experiment).

Answer:

A. if each ecotype is indeed locally adapted as the researchers hypothesized, those adaptations are to other environmental conditions than the water each ecotype inhabits.