amendnent:constitution::________:letter

An Amendment is an addition to a constitution.

With word processors and e-mail, you may not have heard of an addition to a letter.

A postscript (P.S.) is what we used to add to a handwritten or typed letter when we thought of something else we wanted to include after we'd finished and signed the letter. We added the P.S. to the end of the letter.

(a)pain:swelling
(b)irritability:fatigue
(c)conservation:scarcity
(d)blunder:embarassment
(e)skid:icing

aviation : Science

rind:______::skin:apple