单选题 .  ①Soil communities are dependent on plants for organic matter. ②Plants provide organic matter for soil communities through the decomposition of leaf litter, by oozing nutrients from roots, or through other methods of deposition of organic compounds into the soil environments. ③As a result of these diverse methods by which plants supply resources, unique soil communities form under different plant species and under plant communities that differ in composition. ④If a nonnative plant species invades an above-ground community of flora and fauna, it can alter links between the native above-ground community and the below-ground soil community. ⑤For example, an invading nonnative plant could alter the quantity of leaf litter production, which would alter nutrient contributions to the soil.1.  According to the passage, plants supply resources to soil communities by which of the following methods? ______