Which is not true about the cell theory?

Options

A. It states that all organisms are composed of cells
B. It states that all cells come from pre-existing cells
C. It states that bacteria and other small organisms can arise spontaneously
D. It is accepted today by biologists as applying to virtually all forms of life

Explanation

To determine which statement is not true about the cell theory, we can analyze the key points of the cell theory step by step:

### Step 1: Understand the Cell Theory
The cell theory is a fundamental concept in biology that outlines the properties and characteristics of cells. It consists of several key points.

### Step 2: Identify the Key Points of Cell Theory
1. **All organisms are composed of cells**: This means that whether an organism is unicellular (like bacteria) or multicellular (like humans), it is made up of cells.
2. **All cells come from pre-existing cells**: This indicates that cells do not spontaneously generate; they arise from the division of existing cells.
3. **Bacteria and other small organisms can arise spontaneously**: This statement suggests that these organisms can form without the need for existing cells, which contradicts the cell theory.
4. **The cell theory is accepted by biologists as applying to virtually all forms of life**: This means that the principles of cell theory are widely applicable across different life forms.

### Step 3: Analyze Each Statement
- The first statement is true: all organisms are composed of cells.
- The second statement is true: all cells come from pre-existing cells.
- The third statement is false: bacteria and other small organisms cannot arise spontaneously, which is against the cell theory.
- The fourth statement is true: the cell theory is accepted by biologists for all forms of life.

### Conclusion
The statement that is not true about the cell theory is that "bacteria and other small organisms can arise spontaneously." This is incorrect as per the principles of cell theory.

### Final Answer
The statement that is not true about the cell theory is: "Bacteria and other small organisms can arise spontaneously."

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