The term cell membrane was coined by

Options

A. Nageli and Cramer
B. Flemming
C. Sachs
D. Plower

Answer

To answer the question, "The term cell membrane was coined by," we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Options**: The question provides four options:
- A. Nageli and Cramer
- B. Fleming
- C. Sack
- D. Flark

2. **Understand the Concept**: The cell membrane, also known as the plasma membrane, is a selectively permeable barrier that regulates the movement of substances in and out of the cell.

3. **Historical Context**: The term "plasma membrane" was specifically coined in the year 1855.

4. **Research the Correct Answer**: According to historical records, the term was coined by scientists Nageli and Cramer.

5. **Confirm the Answer**: Since the question asks for who coined the term cell membrane, and we know from the information provided that it was Nageli and Cramer, we can conclude that the correct answer is:
- **A. Nageli and Cramer**

### Final Answer:
The term cell membrane was coined by **Nageli and Cramer**.

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