Final answer:
Two different linked photosystems in chloroplasts allow the oxidation of water, overcoming the limitations of anoxygenic photosynthesis, which does not produce oxygen as it uses other molecules as electron donors.
Step-by-step explanation:
Having two different linked photosystems in chloroplasts overcomes the limitations of anoxygenic photosynthesis by allowing the oxidation of water (H2O). In oxygenic photosynthesis, characteristic of plants and cyanobacteria, water serves as the electron donor, replacing electrons in the reaction center of photosystem II. This process leads to the splitting of water molecules, ultimately producing oxygen as a byproduct.
The two photosystems, photosystem I (PSI) and photosystem II (PSII), are excited by light energy and operate in a Z-scheme to facilitate the production of ATP and NADPH. In contrast, anoxygenic photosynthesis, which only employs one photosystem, does not produce oxygen because it uses molecules like H2S or thiosulfate as the electron donor instead of water.