Vestigial structures. These are structural elements that once served a purpose but as the organism evolved now serves no purpose.
I think it is erosion (2) because erosion removes soil, rock, and dissolved material.
Answer:
a scientific theory of the origin of species of plants and animals
It flows through the consumers (first level second level so forth). However, at each level, it loses 90 percent of the energy as heat. So at each level, each consumer will only get 10 percent of the energy.
