The desert survival problem

Individual:81 group:64
At first, I think that I can't survive at desert because of my score so that I don't decide to go to the desert.
I hear that the salt is needed for our body because it includes mineral.
But in fact, it absorbs water, which is very fatal.
I'm very surprised that cosmetic mirror is the most needful thing.
The idea that using cosmetic mirror to reflect light has an novelty.
If I were to leave in a desert, I, considering today's class, would manage to survive.