Examples of mechanical weathering include frost and salt wedging, unloading and exfoliation, water and wind abrasion, impacts and collisions, and biological actions. All of these processes break rocks into smaller pieces without changing the physical composition of the rock.
An energy pyramid is always related to the organisms food web. A increase in no of tropic levels could make it complex. Also the reason for only 4 or 5 is to make it simple to understand.
