Which term refers to a change in the genetic composition of a population over successive generations? 

A)  evolution 
B)  natural selection 
C)  emigration 
D)  mutation

What is one disadvantage of using biomass for energy? 

A)  Large amounts of land are required. 
B)  Its use and application lack versatility. 
C)  Nitrous oxide emissions are higher than for other sources of energy. 
D)  It is not renewable.