In angiosperms,synthesis of chlorophyll occurs in the presence of

$DCMU$ ($3$-($3$,$4$-dichlorophenyl)$-1,1-$dimethylurea) is a chemical that acts as an inhibitor of photosynthesis. What is its specific mode of action?

The Hill reaction takes place in which of the following conditions?

Protons accumulate in the thylakoid lumen due to the . . . . . . .

Absorption of light by chlorophyll of $PS-II$ causes

In photosystem-$I$,the first electron acceptor is