Cells at the end of prophase, when viewed under the microscope do not show_________ .

Options

A. Golgi complexes, endoplasmic reticulum, nucleolus and the nuclear envelop
B. Only nuclear envelope
C. Only endoplasmic reticulum
D. Only nucleolus

Answer

To answer the question, "Cells at the end of prophase, when viewed under the microscope do not show_________," we will analyze the events that occur during prophase in mitosis.

### Step-by-step Solution:

1. **Understanding Prophase**: Prophase is the first stage of mitosis, where significant changes occur in the cell.

2. **Nuclear Envelope Breakdown**: At the end of prophase, the nuclear membrane (nuclear envelope) begins to break down completely. This allows the chromosomes to be released into the cytoplasm.

3. **Chromosomal Condensation**: During prophase, chromatin condenses to form distinct chromosomes, making them more visible under the microscope. By the end of prophase, these chromosomes are fully condensed.

4. **Disappearance of Organelles**: Key organelles such as the endoplasmic reticulum (ER), Golgi apparatus, and nucleolus begin to disappear during prophase. By the end of prophase, they are no longer visible.

5. **Movement of Centrioles**: The centrioles move to opposite poles of the cell, which is a characteristic feature of prophase.

6. **Conclusion**: Given the breakdown of the nuclear envelope and the disappearance of organelles, the structures that are not visible at the end of prophase include the nuclear envelope, nucleolus, and endoplasmic reticulum. However, the question specifically asks for one item that is not visible.

7. **Final Answer**: Therefore, the correct completion of the statement is: "Cells at the end of prophase, when viewed under the microscope do not show the nucleolus."