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.

its hard for me to see which word is supposed to be in bold. if i knew then i would be able to better.

an argumentative essay presents objectively a topic and its main characteristics. besides, it states all this information and facts by giving authentic and substantiated proof to the audience. by contrast, a persuasive text purpose is to convince the audience about some facts by presenting them according to his/her emotions and feelings. the main purpose of a persuasive text is to convince the audience to agree with the author´s opinion. on the other hand, in the argumentative essay, the author leads the writer to recognize his/her point of view as the correct one.