Answer:
This observation in the basis of change in habitat or ecosystem.
Explanation:
At the base of a mountain, we'll most probably find more plants and animals. There will even be trees at the base of mountain. As we move up, there will be a climate change and a change in habitat and ecosystem. There will no trees, fewer number of plants and animals as we go on top of the mountain. All these changes depict that the climate changes the habitat of particular organisms hence, the ecosystem changes.