Final answer:
The triple-alpha process involves the fusion of three helium nuclei to form a carbon nucleus. It occurs at a higher temperature compared to the fusion of hydrogen into helium.
Step-by-step explanation:
The triple-alpha process is a nuclear reaction in which three helium nuclei are fused together to form a carbon nucleus. This process is called the triple-alpha process because it involves the fusion of three alpha particles, which are helium nuclei. The triple-alpha process occurs at a much higher temperature than the nuclear process for fusing hydrogen into helium because the fusion of helium nuclei requires a higher energy input due to the repulsive electromagnetic forces between the positively charged protons.