What organ is about the size of 2 fists that contains acid and enzymes that break down food and kill bacteria?

Which disease is caused by a buildup of plaque in blood ves

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)

Can someone give me a hand with this one.