Answer:
From the last line of the passage of “if you pack it in, pack it out “the author actually meant that a person or individual should take as much as he can have while planning to leave the sand springs.
Step-by-step explanation:
From the given question, what the author refers from the last line of the passage saying “ if you pack it in, pack it out“ is that, logically he is suggesting to the person to take as many things he can place his hands on while and the same time planning to leave the sand springs.