What tiny bumps in the dermis cause the ridges that make up our fingerprints?

Asap indicate the coat color and the proportion of offspring with that color for each of the following crosses of rabbits. assume all are homozygous. alleles: a=agouti, c=chinchilla, a=albino, a is dominant over c and a, c is dominant over a agouti x chinchilla a) 1/2 chinchilla, 1/2 agouti b) 3/4 chinchilla, 1/4 agouti c) all agouti