All ICD-10-CM codes have a first letter. a) For most of the first letters (D-N), the letter means that the items have so

[answerhappygod]

All ICD-10-CM codes have a first letter.
a) For most of the first letters (D-N), the letter means that
the items have something in common. What is it?

b) Other codes (A-C, O – Z) are set up so that the items also
have something in common, but in a different way than D-N.
Give an example
of one categorizing principle
used for one of these. You don’t need to say what
the letter is.