Read the passage below:
For decades, forest ecologists operated under the assumption that subterranean fungal networks serve primarily as passive conduits for nutrient transport between trees. However, recent empirical investigations into Douglas fir stands suggest that these mycovascular connections actively regulate resource distribution in response to microclimatic stressors. Specifically, when mature trees experience localized drought conditions, the fungal hyphae selectively divert carbon compounds to stressed seedlings rather than healthy neighboring adults. This directed allocation challenges traditional models of plant competition by demonstrating a mechanism of cooperative resource sharing mediated by fungal symbionts. Nevertheless, skeptics maintain that such resource transfers are merely incidental byproducts of fungal metabolic demands rather than evolved adaptations for forest resilience. Further comparative studies across varied ecosystems are required to resolve this fundamental debate in plant ecology.
Select the sentence in the passage that provides specific empirical evidence of fungal networks actively diverting nutrients during environmental stress.
Answer: Specifically, when mature trees experience localized drought conditions, the fungal hyphae selectively divert carbon compounds to stressed seedlings rather than healthy neighboring adults. / Specifically, when mature trees experience localized drought conditions, the fungal hyphae selectively divert carbon compounds to stressed seedlings rather than healthy neighboring adults / Sentence 3