Question

which event occurs in photosystem i?
water molecules are broken apart.
light energy excites electrons.
oxygen is released as waste.
electrons are transferred to ferredoxin.

Explanation:

In photosystem I, light - energy is absorbed and used to excite electrons which are then transferred to ferredoxin. Water molecules are broken apart and oxygen is released as waste in photosystem II. Light energy excites electrons in both photosystem I and II, but the key event specific to photosystem I is the electron transfer to ferredoxin.

Answer:

Electrons are transferred to ferredoxin.