Sled dogs have thick fur to keep them warm. But they can overheat while running if it’s too warm outside. The maximum temperature the dogs can run in is 71º higher than their minimum of -71ºF. What is the maximum temperature that they can run in?

-71 + 71 =0 so 0°

Step-by-step explanation:

I hate the fact that it needs to be 20 letters

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.

the answer is b.)

< 1=< 2