Answer:Primary reinforcers
explanation reinforcers that have innate reinforcing qualities.
D. They had larger beaks.
Due to the drought they would need to dig deeper for food. But their tiny beaks could not do that. So over time their beaks grew and adapted to the drought. Therefor the answer is D. They had larger beaks!
Hope this helped! <3
the importance of this procedure is to get a set of data to compare your other test results to, like when they are active
F1 stands for first filial (daughter) generation
<span>F2 stands for second filial (daughter) generation</span>