Which statement is always true when nuclear fusion occurs? (1 point)

The statement that is always true when nuclear fusion occurs is:

**The number of protons in the resulting nucleus is less than in each starting nucleus.**

In nuclear fusion, two light atomic nuclei combine to form a heavier nucleus. During this process, some mass is converted into energy (as per Einstein's equation E=mc²), and typically, the resulting nucleus has fewer total nucleons compared to the sum of the starting nucleons, especially when considering that energy is released in the process. However, the combined number of protons and neutrons does not remain constant; it usually increases.

So, while there might be some nuances to the dynamics of fusion, the most relevant statement in the context of your options is that the resulting nucleus generally has fewer protons than the total from the starting nuclei.