I was wondering if there's a linkage between the geographic distribution of drugs and their effects. There's nicotine, caffeine and cocaine, all originating from south-america and all of them have stimulating effects. On the other hand, drugs like opium and THC have a "eastern" history (coming f...

I can see that variation within species exists, for example birds with various size beaks adapted for specific food-gathering purposes, one may have a larger beak vs. smaller beak, OK that works for me. So my question is, where did the whole bird design come from or cat or dog or mouse? I see no ...

can you tell me how to find solution to this question A DNA chip contains a complete set of random hexanucleotide (6-mers) probes. Out of the 4^6 = 4096 probes, how many will form perfect complementary duplexes with sequences within the single-stranded target DNA, 5'-GAACTGCATTGATA-3'? ...

We know that a person can be infected with HIV viruses when he/she has sexual relationship with those having HIV viruses (and very, very, very rarely, urine/defecation-related transmission) - but I wonder if there are other sources of HIV transmission - so for example, let's say during sexual rel...