1. What are the principal advantages and disadvantages of the COD test over the BOD test.
2. Explain why COD values are greater than BOD values.
3. What would be inferred from the following analyical results regarding the relative ease of biodegrability of each waste?

| Waste type | 5-day BOD (mg/L) | COD (mg/L) |
| ---------- | ---------------- | ---------- |
| A          | 240              | 300        |
| B          | 100              | 500        |
| C          | 120              | 240        |