How come when you look into a mirror right becomes left but up never becomes down?

The image of everything in front of the mirror is reflected backward, retracing the path it traveled to get there. Nothing is switching left to right or up-down. Instead, it's being inverted front to back. That reflection represents the photons of light, bouncing back in the same direction from which they came.

Explanation:

Mirrors don’t reverse left and right. That’s just our interpretation of what happens. Your reflection in the mirror is actually reversed front to back, if you have a mole on the left side of your face, it still appears on the left side of the reflection. But we are used to seeing the faces of other people and we instinctively perform the mental rotation because we know that they have turned through 180 degrees to face us. The image in the mirror is reflected, not rotated, so when we rotate it back in our head, it appears reversed.

ich statement best shows a problem in travels with charley?

one sharp difficulty presented itself. in the intervening twenty-five years my name had become reasonably well known.

this being so, my trip demanded that i leave my name and my identity at home.

i had to go alone and i had to be self-contained, a kind of casual turtle carrying his house on his back.

with all this in mind i wrote to the head office of a great corporation which manufactures trucks.

my guy how are we supposed to know