Question

in the 1800s, the forests of eastern north america were dominated by american chestnut trees. american chestnut trees have nutrient - rich leaves that decay quickly on the forest floor, creating rich soil. in 1904, a fungus arrived in new york on japanese chestnut trees imported by ship. the japanese chestnut trees were resistant to the fungus, but as the fungus spread, it killed almost all the american chestnut trees. today, the forests of eastern north america are dominated by oak trees. oak trees are the preferred food of another introduced species, the spongy moth. the effects of the spongy moth, along with other changes to forest ecosystems, have resulted in the decline of oak trees. in an effort to restore american chestnut trees to forests, scientists have created genetically modified american chestnut trees by incorporating a gene from wheat into the trees genome. the gene allows the trees to resist the fungus by breaking down a toxin produced by the fungus. scientists hope that the genetically modified trees will breed with the remaining american chestnut trees, creating offspring that can resist the fungus. which criterion should the scientists use to best evaluate their solution? a there should be a 50 percent reduction in the spongy moth population. b spongy moths should damage fewer than 50 percent of existing american chestnut trees. c at least 50 percent of young american chestnut trees should be resistant to the japanese chestnut fungus. d the japanese chestnut fungus should be present in more than 50 percent of young american chestnut trees.

Explanation:

The goal is to restore American chestnut trees. Since oak trees have become dominant due to chestnut decline and the spongy moth affects oak trees, reducing the spongy moth population would be beneficial for the overall forest ecosystem and the re - establishment of American chestnut trees. This reduction would create a more favorable environment for the growth of American chestnut trees.

Answer:

a. There should be a 50 percent reduction in the spongy moth population.