Nuclear fusion powers the Sun's core

Steps:

• Identify the process: Fusion of hydrogen to helium releases energy via E=mc², converting mass to energy.
• Recall stellar energy source: Stars like the Sun generate energy through this fusion in their cores.
• Eliminate non-stellar options: Fusion requires extreme heat and pressure, found only in stellar interiors.
• Confirm location: The Sun's core provides the necessary conditions for the proton-proton chain reaction.

Why D is correct:

• In the Sun's core, the proton-proton chain fuses four hydrogen nuclei into helium, releasing energy per Einstein's E=mc² mass-energy equivalence.

Why the others are wrong:

• A: Nuclear power stations use fission of uranium, not hydrogen fusion.
• B: Alpha particle emission is radioactive decay, not fusion of hydrogen to helium.
• C: Earth's core heat comes from radioactive decay and residual formation energy, not fusion.

Final answer: D