I believe the answer is cause
This might be the case due to the lack of beauty they possess. Bayous and swamps typically are dirty, and are filled with insects. Many people would find that as a low standard of beauty.
numbering the steps and adding illustrations
Wait....Exactly what are you confused about?
The main clause is "Chris's chief interest was tennis".
The subordinate clause is "Which he was just learning to play" and it is an adjective clause because it describes what the "tennis" was like. Tennis is an object and this subordinate clause further describes that it is the tennis that he was trying to learn.
