How can you explain that in the mountains the change of altitude zones occurs more sharply and faster

How can you explain that in the mountains the change of altitude zones occurs more sharply and faster than natural zones on the plains, and the natural conditions are more diverse?

As you know, with every kilometer of altitude relative to sea level, the temperature drops by about four degrees. And it is under the influence of the climate in the mountains that high-altitude natural zones are formed. Different climatic conditions determine the variety of natural areas. Since the climate changes dramatically in different parts of the slope due to the height, the natural zones also change frequently. On the plains, the climate does not change so dramatically, and this process occurs only at a distance from the equator.