Final answer:
In the S-state hypothesis, a cluster of 4 manganese ions is stabilized by a water-splitting complex, essential in photosynthetic oxygen evolution.
Step-by-step explanation:
The subject of the question relates to photosynthesis and, more specifically, to the water-splitting component of the photosynthetic apparatus which is crucial for oxygen evolution. In the S-state hypothesis, a cluster of 4 manganese ions are stabilized and protected by a water-splitting complex. This complex plays an essential role in the process by which plants and other photosynthetic organisms use sunlight to split water molecules, releasing oxygen, electrons, and protons necessary for the formation of energy-rich compounds like ATP and NADPH.