In what condition does the Hill reaction occur?

Minerals involved in the photooxidation of water are:

The process of photophosphorylation was discovered by

$P_{680}$ is associated with:

The entire process of photosynthesis consists of a number of reactions. Where in the cell do each of these take place? Synthesis of $ATP$ and $NADPH$ occurs in/at:

Assertion $(A) : H^+$ gradient across the thylakoid membrane is essential for the formation of $\text{ATP}$.
Reason $(R) :$ Breakdown of $H^+$ gradient due to the movement of protons through $F_0$ of $\text{ATP}$ synthase releases enough energy to activate $\text{ATP}$ synthase enzyme that catalyses the formation of $\text{ATP}$.