Answer:
In the given condition, both the gymnosperms and the ferns will decrease in number in the region. The geographical term for the minor tributary of a river is the creek, and when this creek goes through any forest it can function as a water source for the plants growing in the nearby regions.
However, when the same water source, that is, the creek was diverted to the field by the farmer, it affected the growth of ferns and gymnosperms in the forest. This effect was due to the drying up of creek. A reduction in the number of ferns was witnessed as they need water not only for their growth, but also to complete their life cycle.
While at the same time, angiosperms, that is, the flowering plants also showed a reduction in number as they need water to sustain their composition, and also for their proper growth and development. Therefore, both the angiosperms and ferns will reduce in number in the given case.
