The answer could be :It all happened so suddenly.
Answer:
A. In fact, elephants place such huge demands on their own environment, that in order to survive, they often come into conflict, with humans, who are competing for the same resources.
Explanation:
I think this is the answer. The sentence before states that elephants devour several hundred pounds of plant matter in a single day, so this is why i would say "in fact". I'm sorry if this is the wrong answer!
