The splitting up of a water molecule into two hydrogen ions and an oxygen atom by light is called:

Explanation

The correct answer is photolysis of water. In the light-dependent reactions of photosynthesis, light energy is used to split water molecules into oxygen, protons, and electrons. This process, known as photolysis, occurs in the thylakoid membranes of chloroplasts and is essential for the generation of oxygen and the synthesis of energy carriers like ATP and NADPH. Other options, such as electrolysis and ionization of water, do not involve the use of light energy, and autolysis is unrelated to photosynthesis.