Which of the following statements is correct ?
a. rRNA is the most abundant RNA.
b. Ribosomes are composed of approximately 80% rRNA and 20% ribosomal proteins .
c. rRNA is a type of coding RNA .

Options

A. Statements 'a' 'b' and 'c' are correct
B. Statement 'a' is correct
C. Statements 'a' and 'c' are correct
D. Statements 'b' and 'c' are correct

Answer

To determine which of the statements regarding rRNA is correct, let's analyze each statement step by step:

### Step 1: Analyze Statement A
**Statement A:** rRNA is the most abundant RNA.

- **Explanation:** rRNA (ribosomal RNA) is indeed the most abundant type of RNA in the cell. It constitutes a significant portion of the total RNA content, often around 80% of the total RNA in a cell. This makes Statement A correct.

### Step 2: Analyze Statement B
**Statement B:** Ribosomes are composed of approximately 80% rRNA and 20% ribosomal proteins.

- **Explanation:** Ribosomes are made up of rRNA and proteins, but the composition is approximately 60% rRNA and 40% ribosomal proteins, not 80% and 20%. Therefore, Statement B is incorrect.

### Step 3: Analyze Statement C
**Statement C:** rRNA is a type of coding RNA.

- **Explanation:** rRNA is classified as non-coding RNA because it is not translated into proteins. It plays a structural and functional role in the ribosome but does not code for proteins. Thus, Statement C is incorrect.

### Conclusion
After analyzing all three statements:
- Statement A is correct.
- Statement B is incorrect.
- Statement C is incorrect.

Therefore, the correct answer is that **Statement A is the only correct statement.**

### Final Answer
**The correct statement is: A. rRNA is the most abundant RNA.**

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