Soru

Passage:
In plant-fungal ecology, 'asymmetric mutualistic erosion' describes a systemic failure state occurring when an environmental shift selectively alters the cost-benefit ratio for one partner in an obligate symbiosis, prompting that partner to reduce its contribution while continuing to consume resources from the other. Under baseline nutrient-scarce conditions, mycorrhizal fungi supply plants with vital phosphorus in exchange for photosynthetic carbon, maintaining a balanced mutualism. However, when anthropogenic nitrogen deposition artificially enriches soil phosphorus levels, the host plant's reliance on fungal phosphorus drops precipitously. Rather than terminating the association outright, the plant throttles carbon allocation to the fungal network to conserve energy for its own vegetative growth. Crucially, because the fungal network lacks real-time sensory mechanisms to detect the host's carbon restriction, it continues transporting soil minerals to the plant root interface in an attempt to trigger the expected carbon reward. This creates an uncoupled transfer dynamic: the host plant absorbs the fungal metabolic output while withholding its own reciprocal contribution, steadily degrading the fungal network's structural integrity until the provider's infrastructure collapses. Ecologists emphasize that this systemic decay is driven not by active hostility, but by a lagging feedback loop wherein one partner continues fulfilling its performance obligations despite the structural cessation of reciprocal benefits from a counterparty whose reliance has vanished.

Which of the following scenarios is most analogous to the dynamic of 'asymmetric mutualistic erosion' described in the passage?