Assertion : In electron transport system, the electrons are passed on to oxygen resulting in the formation of `H_(2)O`
Reason : Oxygen is the ultimate acceptor of electrons.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion:**
- The assertion states that in the electron transport system (ETS), electrons are transferred to oxygen, leading to the formation of water (H₂O). This is a fundamental process in cellular respiration, particularly during aerobic respiration.

2. **Understanding the Reason:**
- The reason provided is that oxygen acts as the ultimate electron acceptor. In the context of the ETS, this means that after a series of electron transfers through various cytochrome enzymes, the electrons ultimately reach oxygen.

3. **Electron Transport Chain Process:**
- The electron transport system consists of a series of proteins and enzymes (cytochromes) that facilitate the transfer of electrons. As electrons move through the chain, they undergo oxidation-reduction reactions, releasing energy.

4. **Formation of Water:**
- At the end of the electron transport chain, molecular oxygen (O₂) accepts the electrons. Along with hydrogen ions (H⁺) from the cytoplasm, it forms water (H₂O). The reaction can be summarized as:
\[ \frac{1}{2} O_2 + 2 H^+ + 2 e^- \rightarrow H_2O \]

5. **Energy Considerations:**
- The transfer of electrons from higher to lower energy states releases energy, which is used to pump protons across the mitochondrial membrane, creating a proton gradient that ultimately drives ATP synthesis.

6. **Conclusion:**
- Both the assertion and the reason are correct. The assertion accurately describes the process of electron transfer to oxygen resulting in water formation, and the reason correctly identifies oxygen as the ultimate electron acceptor in the electron transport system.

**Final Answer:**
- **Assertion:** True
- **Reason:** True
- **Explanation:** The reason is the correct explanation for the assertion.

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