How does overspecialization cause extinction?

Which description provides the best objective summary of the article in the passage?

What is the best conclusion based on this data? the hypothesis was not supported because the data indicated that fertilizing plants does not improve plant growth. the hypothesis was supported; to get the best growth, use 5 milliliters of fertilizer per plant. the hypothesis was not supported; the data indicated that too much fertilizer can inhibit plant growth. the hypothesis was supported; to get the best growth, use 15 milliliters of fertilizer per plant.

This is the main structural axis of the plant that supports leaves, flowers and fruits; transports fluids; stores nutrients and produces new tissue.