Well-developed pith is found in

The correct option is Monocot root and Dicot stem.

To understand why well-developed pith is present in monocot roots and dicot stems, let us examine the anatomy and distribution of ground tissue in different plant organs:

1. What is Pith?
Pith (or medulla) is a tissue located in the center of the stem or root of vascular plants. It is typically composed of soft, spongy parenchyma cells, which store and transport nutrients throughout the plant.

2. Pith in Roots:
In dicot roots, the vascular bundles (xylem and phloem) are arranged in a small central cylinder, and the pith is either extremely small, poorly developed, or completely absent.
In contrast, monocot roots possess a large, well-developed, and prominent central pith made of parenchymatous cells.

3. Pith in Stems:
In dicot stems, the vascular bundles are arranged in a ring. This ring configuration leaves a large central region filled with parenchyma cells, forming a highly distinct and well-developed pith.
In monocot stems, the vascular bundles are scattered throughout the ground tissue (conjoint, collateral, and closed). Because of this scattered arrangement, there is no distinct separation of ground tissue into cortex and pith; thus, a distinct pith is absent in monocot stems.

Therefore, a well-developed pith is characteristically found in both the monocot root and the dicot stem.