Why can grassland be considered an intermediate condition between dense forests and desert scrub?

Correct answer: Because moisture may be enough for grasses but limited for dense trees

The direct answer is A: moisture may be enough for grasses but limited for dense trees. Grassland is not defined by one exact rainfall value, but it commonly develops where conditions support grasses while limiting continuous, dense tree cover. Step by step: plants need water; where moisture is moderate or seasonal, grasses with shallow or adaptable roots can grow; trees need more sustained moisture and suitable soil for a dense forest; if moisture is insufficient for many trees, grasses remain dominant. A is correct. B is wrong because grasslands do not always have saline water. C is wrong because sunlight is essential for grasses and is normally present. D is wrong because grasslands occur in many plains and other regions, not only on glaciers; glaciers are generally too cold and barren for ordinary grassland. Memory cue: forests need more continuous moisture, while grasslands can manage with moderate or seasonal moisture.