Final answer:
The most obvious way to differentiate between Adenine and Cytosine is through the number of hydrogen bonds they can form.
Step-by-step explanation:
The most obvious way to differentiate between Adenine and Cytosine in their Amino and Imino forms is through the number of hydrogen bonds that they can form. Adenine can form two hydrogen bonds, while Cytosine can form three hydrogen bonds. This difference in the number of hydrogen bonds is due to the structural differences between the two nitrogenous bases.