Under what condition are `C_(4)` plants superior to `C_(3)`

Explanation

`C_(4)` plants are advantageous in following ways.
(i) These plants can carry out photosynthesis even at low concentration of `CO_(2)` in the atmosphere and in the shortage of water.
(ii) These plants can tolerate high `O_(2)` concentration and temperature as enzyme PEP carboxylase in `C_(4)` cycle in insensitive to `O_(2)` and do not show- photorespiration in comparison to the `C_(3)` plants, which start process of photorespiration and lose `CO_(2)` fixation in the form of glucose molecule.
Thus, ` C_(4)` plant are superior to `C_(3)` plants.