Answer:
Nuclear Fusion
The binding energy per nucleon curve (Figure 43.1) peaks at a nucleon number of about 56. This means that nuclei having A = 56 are more tightly bound than either less massive or more massive nuclei. Nuclear fission of nuclei with A ≈ 240 releases energy because the fragments have mass numbers closer to the A = 56 peak and are therefore more tightly bound. Nuclear reactions between light nuclei that produce more massive and more tightly bound nuclei also release energy.