The diagram above shows the progression of ecological events after a fire in a particular ecosystem. Based on the diagram, which of the following best explains why the oak trees are later replaced by other trees?
- A Eventually the other trees grow taller than the oak trees and form a dense canopy that shades the understory.
- B Oak trees alter the pH of the soil, making the forest better suited for shrubs and other trees.
- C Roots of shrubs proliferate in the soil of the forest and prevent the oak trees from obtaining water.
- D Oak trees succumb to environmental pollutants more readily than do either the shrubs or the other trees.
