The two photosystems (PS-I and PS-II) are connected through an 

The two photosystems (PS-I and PS-II) are connected through an electron transport chain. During the light-dependent reactions, both photosystems absorb light energy and transfer it to chlorophyll molecules. In PS-II, light energy is used to split water molecules into oxygen, protons (H⁺ ions), and electrons. These electrons are then passed through an electron transport chain located in the thylakoid membrane, known as the electron transport chain of PS-II. The electrons eventually reach Photosystem I (PS-I) through the electron transport chain.