Final answer:
The removal of a keystone species can result in the emergence of alternative community states, a reduction in species diversity, and the simplification of energy pathways.
Step-by-step explanation:
The correct answer is d) all of the above. Removal of a keystone species can have several consequences in an ecological community. It can lead to the emergence of alternative community states, where the community structure shifts to a different state. It can also result in a reduction of species diversity as certain species are no longer able to thrive without the presence of the keystone species. Additionally, the removal of a keystone species can simplify pathways for energy transfers, as the absence of the keystone species may disrupt the flow of energy within the ecosystem.