Hey there,
Your question states: Which of the following best explains why zoos are not affected by the threat of new entrants?
Based on the option's above, I feel like the answer would be (Starting a zoo has a high entry cost.) Because by doing this, this could make to (zoo) in better quality. So when things go down like (a cage) for example, they could easily pay it back with all the extra money they have.
Hope this helps.
~Jurgen
