Oxygen acts as the final hydrogen acceptor in electron transport chain of mitochondria.

Answer

**Step-by-Step Solution:**

1. **Understanding the Electron Transport Chain (ETC):**
- The electron transport chain is a series of protein complexes and other molecules located in the inner mitochondrial membrane. It plays a crucial role in cellular respiration, particularly in the process of oxidative phosphorylation.

2. **Role of Oxygen in the ETC:**
- Oxygen is essential for aerobic respiration. It acts as the final electron acceptor in the electron transport chain. This means that after electrons have passed through the various complexes of the ETC, they are ultimately transferred to oxygen.

3. **Formation of Water:**
- When oxygen accepts electrons, it combines with protons (hydrogen ions) to form water. The reaction can be summarized as:
\[ \text{O}_2 + 4e^- + 4H^+ \rightarrow 2H_2O \]
- Here, \( e^- \) represents electrons, and \( H^+ \) represents protons.

4. **Production of ATP:**
- As electrons move through the electron transport chain, they release energy. This energy is used to pump protons across the mitochondrial membrane, creating a proton gradient. The flow of protons back into the mitochondrial matrix through ATP synthase drives the production of ATP from ADP and inorganic phosphate.

5. **Conclusion:**
- Therefore, the statement "Oxygen acts as the final hydrogen acceptor in the electron transport chain of mitochondria" is true. Oxygen's role is critical for the completion of the electron transport chain, leading to the production of water and ATP.

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