Stem
The stem of a plant is responsible for carrying water and nutrients from the roots to other parts of the plant. This process is crucial for the plant's growth and survival.

Functions of the Stem:
- **Transportation:** The stem contains vascular tissues, such as xylem and phloem, which help in the transportation of water and nutrients. Xylem carries water and minerals from the roots to the leaves, while phloem transports sugars produced during photosynthesis to other parts of the plant.
- **Support:** The stem provides support to the plant, holding up the leaves, flowers, and fruits. It helps the plant to stand upright and ensures proper exposure to sunlight for photosynthesis.
- **Storage:** Some stems are modified to store food and water, such as in cacti. These stored resources can be used during times of drought or scarcity.

Structure of the Stem:
- **Epidermis:** The outer layer of the stem that protects it from external factors.
- **Vascular Tissues:** Xylem and phloem are located in the stem and are responsible for the transportation of fluids.
- **Cortex:** The region between the epidermis and vascular tissues that provides additional support and storage.
- **Cambium:** A layer of cells that divide to produce new xylem and phloem cells, allowing the stem to grow in girth.
In conclusion, the stem plays a vital role in the overall functioning of a plant by transporting water and nutrients from the roots to other parts of the plant. Its structure and functions are essential for the plant's growth, development, and survival.