Which of the following pair is having iron as an import constituent?

Options

A. Enzyme A and Thiamine
B. Cyotien and Cytochrome
C. Biotini and Thiamine
D. boron

Answer

To determine which pair contains iron as an important constituent, we can analyze each option provided:

1. **Option A: Enzyme A and Thiamine**
- Thiamine (Vitamin B1) is primarily associated with carbohydrates and does not contain iron as a significant component. Enzymes can vary, but without specific information about "Enzyme A," we cannot confirm iron's presence.

2. **Option B: Cysteine and Cytochrome**
- Cysteine is an amino acid that contains sulfur, while cytochromes are proteins that play a crucial role in electron transport and cellular respiration. Cytochromes contain heme groups, which are iron-containing compounds. Therefore, this pair does include iron as an important constituent.

3. **Option C: Biotin and Thiamine**
- Biotin (Vitamin B7) is involved in fatty acid synthesis and amino acid metabolism, while thiamine is involved in carbohydrate metabolism. Neither of these vitamins is known for containing iron.

4. **Option D: Boron**
- Boron is a chemical element and does not contain iron. It is not a pair but a single element.

Based on this analysis, the correct answer is **Option B: Cysteine and Cytochrome**, as cytochromes contain iron as an essential component.

### Steps Summary:
1. Analyze each option to identify the components.
2. Determine the role of each component in relation to iron.
3. Conclude which pair contains iron.