if it's 'respond' then you can write whatever
if it's 'discuss' then you have to be balanced... im sure you know the rest...
ideas:
universality of themes - each theme remains central to an aspect of society (human relationships) and the ideas have changed due to circumstance/context
e.g. because people haven't changed, the nature of relationships between the characters are similar; however, this does not mean that the ideas have been 'borrowed' from another text
you could also talk about how genre(both are satires) and basic types of stories are frameworks for many different stories, all similar, but each different and UNIQUE (yeah... time for all those buzzwords)...
e.g. happy love story, tragic love story, growing up/coming of age story, western
hope that helped and gluck