Buffer zones
a. can regulate the acidity of aquatic ecosystems
b. increase erosion rates
c. are set up around natural resource areas
d. all of the above

The correct answer is letter D. All of the above choices describe the importance of buffer zones. They are zonal areas that segregate or conjoin regions or countries. They are usually set up in countries to protect the environment, prevent violence, protect people and commercial zones from accidents and natural disasters. 

Centriole.centrioles are present in animal cells but are usually absent in plant cells.