2.if you are working as a forensic scientist and are given an unknown powder from a crime scene, what would you hope to find out about the powder?

3. you find that the unknown powder contains the illegal drug cocaine. if someone where to ask you to determine the purity of the substance, what would they mean? why is purity important in crime investigations?

4.of the controlled substances, which schedule of drugs is the average person most likely to have in their homes? how are the controlled substances in this group different from those in the other schedule levels?

If you are working as a forensic scientist and are given an unknown powder from a crime scene, what would you hope to find out about the powder?

If I am working as a forensic scientist and I am given  an unknown powder, I would analyze this and hope to find out where did this belong.

You find that the unknown powder contains the illegal drug cocaine. If someone where to ask you to determine the purity of the substance, what would they mean? Why is purity important in crime investigations?

The purity of the substance would mean that how much of the main component of cocaine is present in this powder. Purity is important in crime investigations because it will help you determine how much of the main component is present in that substance, the main component is the active ingredient of that substance.
Of the controlled substances, which schedule of drugs is the average person most likely to have in their homes? How are the controlled substances in this group different from those in the other schedule levels?

The schedule of drugs that is mostly present at home is antibiotics.

"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."