Which feature is characteristic of dicotyledons?

Dicotyledons, commonly referred to as dicots, are a major group of flowering plants characterized by specific features, one of which is the net-like pattern of leaf veins. This venation pattern, also known as reticulate venation, allows for an efficient distribution of nutrients and water throughout the leaf, supporting processes such as photosynthesis.

In contrast, monocotyledons (or monocots) typically exhibit parallel venation, where the leaf veins run alongside each other in a straight line. The net-like arrangement in dicots contributes to their adaptability and diverse morphological traits. This feature can be observed in many common plants, such as oak trees and sunflowers, which display this distinct leaf vein pattern.

The other choices do not accurately reflect the traits of dicots. Long slender leaves are more characteristic of some monocots, round stems with hollow internodes could suggest certain monocots like grasses, and wider spacing between leaves is not a definitive characteristic of dicots as leaf arrangement varies significantly among plant species. Thus, the characteristic net-like leaf veins affirm the identity of a plant as belonging to the dicotyledon group.