Many minerals are absorbed in small intestine which are required for maintaining normal physiology of the human body. Find out which of the following is correct statement for minerals?

Options

A. Sodium - Principal cation of interstitial fluid and needed for normal blood clotting
B. Potassium - Component of enzymes like carbonic anhydrase and pigments like myoglobin
C. Chlorine - Principal cation of cytoplasm and required for the activity of ptyalin
D. Phosphorus - A component of RNA

Answer

To solve the question regarding the correct statement for minerals, we will analyze each option provided in the question step by step.

### Step 1: Analyze Option 1
**Statement**: Sodium, principal cation of interstitial fluid and needed for normal blood clotting.

- **Analysis**: Sodium (Na+) is indeed the principal cation of interstitial fluid and plays a crucial role in maintaining osmotic balance and fluid balance in the body. However, the statement claims that sodium is needed for normal blood clotting, which is incorrect. Calcium (Ca2+) is the mineral primarily responsible for blood clotting.

**Conclusion**: This statement is incorrect.

### Step 2: Analyze Option 2
**Statement**: Potassium, component of enzymes like carbonic anhydrase and pigments like myoglobin.

- **Analysis**: Potassium (K+) is essential for various physiological functions, including maintaining osmotic balance and nerve function. However, it is not a component of carbonic anhydrase or myoglobin. Carbonic anhydrase is actually dependent on zinc (Zn2+) as a cofactor, and myoglobin contains heme, which is an iron-containing pigment.

**Conclusion**: This statement is incorrect.

### Step 3: Analyze Option 3
**Statement**: Chlorine, principal anion of cytoplasm and required for the activity of ptyalin.

- **Analysis**: Chlorine (Cl-) is indeed a principal anion in the body, particularly in extracellular fluid. However, ptyalin (salivary amylase) does not require chlorine for its activity. Ptyalin is an enzyme that breaks down starches and does not have a known requirement for chlorine.

**Conclusion**: This statement is incorrect.

### Step 4: Analyze Option 4
**Statement**: Phosphorus, a component of RNA.

- **Analysis**: Phosphorus (P) is a vital component of nucleic acids, including RNA and DNA. It forms part of the backbone of these molecules, linking nucleotides together. This statement is accurate.

**Conclusion**: This statement is correct.

### Final Answer
The correct statement regarding minerals is:
**Option 4: Phosphorus, a component of RNA.**

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