By tar, I think you mean nicotine. (I Hope). It affects the nerve signals that regulate breathing.
I would say D. small intestine
If you want an explanation, here it is
After leaving the stomach, water is absorbed mostly in the early segments of the
small intestine, the duodenum, and the jejunum. A small portion of all water absorption occurs in the stomach and the colon: the small intestine absorbs 6.5L/day, whereas the colon absorbs 1.3L/day.
Hiv doesnt kill people if they are taking their medicine they can live a long life but because their t-cell so like people who are not affected say they get a cold they can get over it in like a month a cold can kill a person with hiv because there system is not that strong .well i think
