Take a or e as a reference. No "neck" like b or k, nor "tail" like g or p. The line is the size of the letter a. I think it helps recognizing words faster and may also be of help when learning cursive (yes I know the letters here aren't cursive but it's one of the first steps).
It just seems that if you can read the instructions, the exercise itself is redundant, as you can obviously read. It's just a waste of time at that point.
bag-3
pen-1
fish-4
egg-6
chair-2
nose-5
Fish = box 4
Egg = box 6
Chair = box 2
Nose = box 5