1. the absolute age of a rock is expressed with
o a. dates in roman numerals
o b. geologic symbols for rock layers
oc. comparisons to the age of other rocks.
c d. numerical age, in years.

Group of genes that encode molecules found in all body cells, creating a biochemical “fingerprint” that serves as the “id” for cells so that they are marked as “self” a) deoxyribonucleic acid (dna) b) entry inhibitors c) major histocompatibility complex (mhc) d) non-nucleoside reverse transcription inhibitors (nnrtis)