Cell is the basic unit of life. Discuss in brief.
The cell is called the basic unit of life because it is the smallest structure capable of independent existence and performing essential functions of life. All living organisms, whether unicellular (composed of a single cell) or multicellular (composed of many cells), are made up of cells.
Anything less than a complete structure of a cell does not ensure independent living. Hence, the cell is the fundamental structural and functional unit of all living organisms. The cell theory emphasizes the unity underlying the diversity of life forms, stating that all living organisms are composed of cells and products of cells, and all cells arise from pre-existing cells.
The presence of cells in all living organisms is what distinguishes them from non-living things, making the cell essential for life.
Explanation
This answer covers the key points from the textbook: (1) cells are present in all living organisms, (2) unicellular organisms can exist independently and perform essential life functions, (3) anything less than a complete cell cannot ensure independent living, (4) cell is the fundamental structural and functional unit, and (5) the cell theory's key principles. The answer is within the 80-120 word limit for a 3-mark question.