Read the following statements w.r.t. archaebacteria : [(a)methanogens converts CO_2 and formic acid into methane, (b) halophiles develop a pigmented membrane to herness sun's energy, (c) All methanogens are heterotrophs. , (d) Thermoacidophiles oxidies sulphur to sulphuric acid under aerobic conditions., (e) methanogens and halophiles are present in guts of ruminant animals.]

Options

A. (a),(b),(d) and (e)
B. (a), (b), (c),(d) and (e)
C. (b), (c), (d) and (e)
D. (a),(b) and (d)

Answer

To analyze the statements regarding archaebacteria, let's evaluate each one step by step:

### Step 1: Evaluate Statement (a)
**Statement:** Methanogens convert CO₂ and formic acid into methane.

**Analysis:**
- Methanogens are a type of archaebacteria that are known for their ability to produce methane. They utilize carbon dioxide (CO₂) and formic acid as substrates to produce methane (CH₄).
- This statement is **true**.

### Step 2: Evaluate Statement (b)
**Statement:** Halophiles develop a pigmented membrane to harness the sun's energy.

**Analysis:**
- Halophiles are another category of archaebacteria that thrive in high-salt environments. They possess a pigmented membrane known as bacteriorhodopsin, which allows them to absorb sunlight and generate ATP.
- This statement is **true**.

### Step 3: Evaluate Statement (c)
**Statement:** All methanogens are heterotrophs.

**Analysis:**
- Methanogens are primarily classified as chemoautotrophs, meaning they can utilize inorganic substances (like CO₂) to produce their own food. They are not classified as heterotrophs, which rely on organic compounds for nutrition.
- This statement is **false**.

### Step 4: Evaluate Statement (d)
**Statement:** Thermoacidophiles oxidize sulfur to sulfuric acid under aerobic conditions.

**Analysis:**
- Thermoacidophiles are archaebacteria that thrive in extremely hot and acidic environments. They can oxidize sulfur to sulfuric acid, especially in the presence of oxygen (aerobic conditions).
- This statement is **true**.

### Step 5: Evaluate Statement (e)
**Statement:** Methanogens and halophiles are present in the guts of ruminant animals.

**Analysis:**
- Methanogens are indeed found in the guts of ruminant animals, where they help in the digestion process by producing methane. However, halophiles are typically found in saline environments and are not associated with the guts of ruminants.
- This statement is **false**.

### Conclusion:
After evaluating all the statements:
- **True Statements:** (a), (b), (d)
- **False Statements:** (c), (e)

Thus, the correct statements are A, B, and D.

### Final Answer:
The correct statements are A, B, and D.

---