Answer:
Nucleic Acids
Step-by-step explanation:
Nucleic acids are DNA and RNA and they are the molecules responsible for containing the genetic material of all living beings. Thus, DNA and RNA are the molecules responsible for establishing the variability and different characteristics between dog breeds, through the genetic information that each of them houses.
In this case, among the options given in the question above, we can confirm that if Allen has studied the genetic material of dogs to better understand why there are so many different breeds, he must have studied nucleic acids.