1.Which organisms are used for high yield of vitamin B12? A)Unicellular bateria
B)Genetically modified bacteria
C)Multi cellular organisms
D)Viruses

Large scale industrial production of vitamin B12 occurs via microbial fermentation, predominantly utilizing Pseudomonas denitrificans, Propionibacterium shermanii, or Sinorhizobium meliloti [7].

Vitamin B12 is produced by microbial fermentation, using strains such as P. denitrificans and P. shermanii.

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."