[[1]]  is the arrangement of veins and veinlets in the lamina of a leaf.

Concept: Venation is the arrangement of veins and veinlets in the lamina of a leaf. The most significant vegetative structure is leaves. They take part in photosynthesis. Simple leaves have three major venation patterns: palmate, pinnate, and parallel. A prominent center vein (the midrib) usually runs from the leaf base to the tip.
Hence, Venation is the correct answer.