Step-by-step explanation:
The cell theory is a fundamental concept in biology that describes the basic properties of cells. It consists of three main principles, and one of them is the presence of organisms. The three principles of the cell theory are:
1. **All living organisms are composed of cells:** This principle states that every living entity, from the smallest microorganism to the largest animal or plant, is made up of one or more cells. Cells are the structural and functional units of life.
2. **The cell is the basic functional unit of life:** This principle emphasizes that all the functions and processes of life occur within cells. Cells are responsible for carrying out the essential functions of an organism, such as metabolism, growth, and reproduction.
3. **All cells arise from pre-existing cells:** This principle, attributed to Rudolf Virchow, emphasizes that new cells are generated from existing cells through processes like cell division (e.g., mitosis or meiosis). Cells do not spontaneously arise from non-cellular matter (a concept known as spontaneous generation).
So, the correct answer is that all three of these principles are part of the cell theory. "Organism" is not a principle of the cell theory; it is a broader concept that encompasses the principles of the cell theory as they relate to living entities.