The arms are what to the legs?

Frankie is having difficulty developing a friendship with histeammate curtis. whenever frankie invites curtis to hangout with him at the park, curtis always says that he's busy.what is most likely preventing a healthy relationship fromforming? a)the boys are not being generous with their time andeffort.b)the boys are not communicating.c)both boys are too busy.d)the boys are on different teams.

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)

In which book word demography is used for first time