`Mg` and `Zn` have the following resemblance:

Options

A. `MgO` and `ZnO` are amphoteric.
B. `MgCO_(3)` and `ZnCO_(3)` both on heating give corresponding oxide.
C. Both are used as electrodes.
D. Both are used to prevent corrosion

Answer

To determine the resemblance between magnesium (Mg) and zinc (Zn), we will evaluate the four statements provided in the question.

### Step-by-Step Solution:

1. **Evaluate the first statement: "MgO and ZnO are amphoteric."**
- Magnesium oxide (MgO) is primarily a basic oxide, meaning it reacts with acids but not with bases.
- Zinc oxide (ZnO), on the other hand, is amphoteric, as it can react with both acids and bases.
- **Conclusion:** This statement is **false** because MgO is not amphoteric.

2. **Evaluate the second statement: "MgCO3 and ZnCO3 both on heating give corresponding oxide."**
- When magnesium carbonate (MgCO3) is heated, it decomposes to form magnesium oxide (MgO) and carbon dioxide (CO2):
\[ \text{MgCO}_3 \rightarrow \text{MgO} + \text{CO}_2 \]
- Similarly, zinc carbonate (ZnCO3) also decomposes upon heating to produce zinc oxide (ZnO) and carbon dioxide (CO2):
\[ \text{ZnCO}_3 \rightarrow \text{ZnO} + \text{CO}_2 \]
- **Conclusion:** This statement is **true**.

3. **Evaluate the third statement: "Both are used as electrodes."**
- Both magnesium and zinc can be used as electrodes in electrochemical cells. They can serve as anodes due to their ability to lose electrons easily.
- **Conclusion:** This statement is **true**.

4. **Evaluate the fourth statement: "Both are used to prevent corrosion."**
- Magnesium and zinc are both used in corrosion prevention methods. They can form protective oxide layers that inhibit further corrosion. Zinc is commonly used in galvanization to protect iron and steel, while magnesium is used in various alloys and coatings.
- **Conclusion:** This statement is **true**.

### Final Conclusion:
Based on the evaluations:
- The first statement is **false**.
- The second, third, and fourth statements are **true**.

Thus, the correct options are **B, C, and D**.