______ is the pattern of veins in the blade of a leaf.

Venation

The correct answer is Option (4) -Venation

Venation refers to the arrangement or pattern of veins in the blade or lamina of a leaf. It describes how the veins are distributed throughout the leaf and how they branch and connect to each other. This pattern is important for the transportation of water, nutrients, and other substances within the leaf. There are two main types of venation: parallel venation, where the veins run parallel to each other along the length of the leaf, and reticulate or netted venation, where the veins form a branching network throughout the leaf. The type of venation can be used as a characteristic feature for classifying and identifying different plant species.