Stroma in biology refers to the fluid present between the grana, where the reactions for the formation of carbohydrate takes place in the chloroplast of plant cells taking part in the process of photosynthesis.
Part A:
In the bright daylight, the Calvin cycle takes place within the stroma. Throughout the Calvin cycle, the outcomes, that is, the ATP and NADPH are the conventional convert molecules of carbonic acid gas into high energy sugars.
Part B:
In the darkness, the Calvin cycle conjointly takes place within the stroma. Through the Calvin cycle, the products ATP and NADPH are used to convert the molecules of carbon dioxide into the high energy sugars.
Part C:
There will be a reduction in the formation of ATP and NADPH if the plants are kept in the dark for an extended time duration and also the Calvin cycle cannot be sustained.