The concept of unit membrane was propounded by
(a) Danielli
(b) Davson
(c) Robertson
(d) Both a and b

Options

A. Danielli
B. Davson
C. Robertson
D. Both (1) and (2)

Answer

To solve the question regarding who propounded the concept of the unit membrane, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks who proposed the concept of the unit membrane. The options provided are Danielli, Davson, Robertson, and a combination of Danielli and Davson.

2. **Identify Key Terms**: The term "unit membrane" is crucial. It refers to a specific model of biological membranes.

3. **Research the Contributors**:
- **Danielli and Davson**: They are known for proposing the "biomembrane model" which describes the structure of biological membranes but not specifically the unit membrane concept.
- **Robertson**: He is credited with the proposal of the "unit membrane model" around the year 1959.

4. **Analyze the Options**:
- Option (a) Danielli: Incorrect, as he did not propose the unit membrane.
- Option (b) Davson: Incorrect, similar to Danielli.
- Option (c) Robertson: Correct, as he proposed the unit membrane model.
- Option (d) Both a and b: Incorrect, since neither proposed the unit membrane.

5. **Conclusion**: Based on the analysis, the correct answer is (c) Robertson.

### Final Answer:
The concept of unit membrane was propounded by (c) Robertson.

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