The passage given below is followed by four alternate summaries. Choose the option that best captures the essence of the passage.
Forests have long been imagined as competitive arenas in which trees fight for light, water, and minerals; a closer look beneath the soil suggests the metaphor is incomplete. Threads of fungus weave through roots and link individual trees — often of different species — into networks that ferry sugars and chemical alarms between them. A shaded sapling can receive carbon from neighbours still in sunlight, and an injured tree can warn its kin nearby. The forest has not stopped competing, but it cooperates as well, in ways the older account obscured.