AP BIOLOGY

Detailed explanation-1: -The herbaceous stem is composed of vascular bundles (xylem and phloem) arranged in a circle around a central core of spongy tissue made up of parenchyma cells, called the pith. Surrounding the vascular bundles is a layer known as the cortex, which varies in thickness from species to species.

Detailed explanation-2: -In dicot stems, the vascular bundles are arranged in a ring. Like dicot roots, dicot stems are protected by an outer layer of dermal tissue called the epidermis. Then, also similar to dicot roots, dicot stems have a layer of ground tissue called the cortex beneath the epidermis.

Detailed explanation-3: -In herbaceous plants, it occurs in the vascular bundles which are often arranged like beads on a necklace forming an interrupted ring inside the stem. In woody plants, it forms a cylinder of unspecialized meristem cells, as a continuous ring from which the new tissues are grown.

Detailed explanation-4: -While the circulatory system is responsible for this task in humans, plants have structures called xylem and phloem that move resources like water and sugars from one place to another. Typically, xylem and phloem are grouped together in vascular bundles, that allow water to be exchanged between the two as needed.