Consider the given two statements:
| I: | A double-stranded DNA rich in G and C needs more energy to be broken than one that is rich in A and T. |
| II: | While the ratio of G to C and A to T in an organism's DNA is fixed, the GC content can vary considerably from one DNA to another. |
| 1. | Both I and II are correct and II explains I |
| 2. | Both I and II are correct but II does not explain I |
| 3. | I is correct and II is incorrect |
| 4. | Both I and II are incorrect |