Which of the following is a concept of the cell theory? A. Only higher organisms are composed of cells. B. A cell is the basic structural and functional unit of living organisms. C. Simple cells can arise spontaneously from rotting vegetation. D. The subcellular organelle is the basic unit of life.

The answer is B. A cell is the basic structural and functional unit of living organisms.

Explanation:

Cell theory is a fundamental part of biology that explains the constitution of living matter based on the cell and the role they play in the constitution of life. This theory specifies how cells are fundamental and important for the existence of life and how they determine the most important characteristics of living beings.