Cairo, Egypt, in its history[?] has had a significant number of fortified gates protecting both inner and outer city. Apart from the purpose of defense they were also used for differentiation of the varied social and economic classes. Often the gates were heavily decorated as artistic pieces.
... Light-dependant reaction
2.1 Cyclic photophosphorylation
2.2 Noncyclic photophosphorylation
3 The Calvin cycle
The production of oxygen
It is interesting to note ...