The cell is often referred to as the structural and functional unit of life because it is the smallest entity that can perform all the essential functions necessary for life. Below, we will explore the reasons why the cell is considered as such:

1. Structure of the Cell:
The cell is a highly organized structure that is composed of various components, each with a specific function. These components include the cell membrane, cytoplasm, organelles, and genetic material. All of these structures work together to ensure the proper functioning of the cell.

2. Basic Unit of Life:
Cells are the building blocks of all living organisms. Every living organism, whether it is a plant, animal, or microorganism, is made up of one or more cells. Cells are capable of carrying out all the processes necessary for life, such as growth, reproduction, and metabolism.

3. Cellular Processes:
Cells are responsible for performing a wide range of functions that are essential for the survival and maintenance of an organism. These functions include nutrient uptake, waste removal, energy production, protein synthesis, and cell division. Each of these processes is carried out by specific organelles within the cell.

4. Specialized Cells:
Different types of cells have specific functions and structures that enable them to carry out specialized tasks. For example, nerve cells are responsible for transmitting electrical signals, while muscle cells are specialized for contraction. These specialized cells work together in tissues and organs to perform complex functions.

5. Reproduction:
Cells are capable of reproducing and giving rise to new cells. This process is vital for the growth and development of an organism. Through cell division, one cell can give rise to two identical daughter cells. This is the basis of growth, tissue repair, and reproduction.

6. Genetic Information:
Cells contain genetic material in the form of DNA (deoxyribonucleic acid). DNA carries the instructions for the development, functioning, and reproduction of living organisms. This genetic information is passed on from one generation to another through the replication and division of cells.

In conclusion, the cell is called the structural and functional unit of life because it is the smallest entity that can perform all the necessary functions for life. Cells are highly organized structures that carry out various processes essential for the survival and maintenance of an organism. They are the building blocks of all living organisms and contain genetic information that is passed on from generation to generation. Specialized cells work together in tissues and organs to perform complex functions. The cell's ability to reproduce and carry out a wide range of processes makes it the fundamental unit of life.