Which component of cell theory states that all living things are made up of cells?

The statement that all living things are made of one or more cells is a fundamental concept of cell theory, which underscores the biological principle that cells are the basic building blocks of all life forms. This idea emphasizes that whether an organism is unicellular, like bacteria, or multicellular, like plants and animals, cells are the essential units that make up their structure and function.

Each cell carries out life processes and functions necessary for the organism's survival. The concept is critical in biology as it lays the foundation for understanding how living organisms are classified, how they grow and develop, and how they function at both a cellular and systemic level. This principle also connects to other essential concepts in biology, including metabolism, growth, and reproduction, all of which take place at the cellular level.

In contrast, other statements do not capture the essence of what constitutes living organisms within cell theory. For instance, stating that cells are not the basic unit of life contradicts the very concept of cell theory. The assertion that all cells arise from pre-existing cells describes the process of cell division rather than the makeup of living organisms. Claiming that cells are only found in animals ignores the vast diversity of life that includes plants and microorganisms, which also consist of cells. Each of