Answer:
The DNA of an amphibian, such as a frog, is different from the DNA in a human because a frog's DNA contains a different number and sequence of nitrogenous bases (option A).
Step-by-step explanation:
DNA is the molecule that contains all the genetic information of the different species of living beings, being a molecule that is present in all of them.
Although the DNA of all living beings has the same basic structure —four nitrogenous bases, a deoxyribose and a phosphate group— what makes the differences between species is the length of the DNA molecule and the different sequences of nitrogenous bases present in the molecule. It is for this reason that frog DNA is different from human DNA.
The other options are not correct because:
B. There are no differences in the phosphate groups from one species to another.
C. All DNA molecules contain guanine and adenine.
D. Hydrogen bonds between nitrogenous bases depend on the amount of paired bases, but are not related to differences in DNA between species.