The torus structure in bordered pits of conifer tracheids is critical for maintaining water transport during periods of drought or freezing. This structure prevents air bubbles formed during cavitation from spreading into adjacent tracheids. However, in some tropical conifer species, where drought and freezing are not prevalent, the torus structure is absent. Therefore, the torus structure is an adaptation specifically evolved to address environmental stresses like drought and freezing, rather than a universal feature of conifer water transport.
Which one of the following most accurately expresses the main conclusion of the argument?
Answer: