In the following given options which one is mismatch?

Options

A. Oxygen - Most abundant element in human body as well as earth`s crust
B. Retentate - Macromolecule containing insoluble fraction
C. Proteins - Homopolymer
D. Carotenoids - Secondary metabolites

Answer

To solve the question of identifying the mismatch among the given options, we will analyze each statement one by one and determine their validity.

### Step 1: Analyze the first statement
The first statement claims that oxygen is the most abundant element in the human body as well as in the earth's crust.

- **Analysis**:
- In the human body, oxygen constitutes about 65% of its mass.
- In the earth's crust, oxygen makes up approximately 46%.

Since both claims are true, this statement is **correct**.

### Step 2: Analyze the second statement
The second statement states that the retentate is the macromolecular fraction which contains the insoluble fraction.

- **Analysis**:
- When a biological sample is treated with trichloroacetic acid, it separates into two fractions: the insoluble fraction (retentate) and the soluble fraction (filtrate).
- The retentate indeed contains macromolecules, which are larger and insoluble in the acid.

This statement is also **correct**.

### Step 3: Analyze the third statement
The third statement claims that proteins are homopolymers.

- **Analysis**:
- Proteins are made up of long chains of amino acids, and there are 20 different amino acids that can be combined in various sequences to form proteins.
- Since proteins are composed of different types of amino acids, they are classified as heteropolymers, not homopolymers.

This statement is **incorrect** and is the mismatch.

### Step 4: Analyze the fourth statement
The fourth statement mentions that carotenoids are secondary metabolites.

- **Analysis**:
- Carotenoids are indeed classified as secondary metabolites produced by plants. They are not directly involved in the primary metabolic processes but serve various functions, including pigmentation.

This statement is **correct**.

### Conclusion
The only mismatch among the statements is the third statement, which incorrectly classifies proteins as homopolymers instead of heteropolymers. Therefore, the answer to the question is:

**Option 3: Proteins are homopolymers (incorrect statement).**

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