E.R. was discovered from

Options

A. Liver cells
B. Kindey cells
C. Muscle cells
D. Nerve cells

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the origin of the discovery of the endoplasmic reticulum (E.R.).

2. **Identifying the Options**: The options provided are:
- 1st: Liver cells
- 2nd: Kidney cells
- 3rd: Muscle cells
- 4th: Nerve cells

3. **Historical Context**: The endoplasmic reticulum was first observed in the year 1897 by a scientist named Garnier.

4. **Observation Details**: Garnier used a light microscope to observe the endoplasmic reticulum.

5. **Specific Cell Type**: The endoplasmic reticulum was specifically observed in hepatocytes, which are the cells of the liver.

6. **Function of E.R.**: The endoplasmic reticulum plays a crucial role in the biosynthesis of lipids and proteins, but this is not directly related to the discovery.

7. **Conclusion**: Based on the historical context and the specific cell type where E.R. was first observed, the correct answer is that the endoplasmic reticulum was discovered from liver cells.

**Final Answer**: The endoplasmic reticulum (E.R.) was discovered from liver cells.

---