The process of nuclear fusion in stars primarily releases energy, which is fundamental for the heat and light emitted by stars. Additionally, it results in a loss of mass, according to the mass-energy equivalence principle. Therefore, the correct answer to the question is A. energy.
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Nuclear fusion in stars primarily releases energy , which is essential for the light and heat produced by stars. It also results in a loss of mass and increases internal pressure. The fusion process is vital for a star's energy balance and stability. ;