A geologist is studying a new soil profile. In analyzing the profile, she finds that the topsoil is rich in organic material. She concludes that this soil would be great for growing crops.

What materials combined to form the topsoil?

1. weathered bedrock and wind-blown sand
2. decomposed humus and wind-blown sand
3. decomposed plant litter and weathered parent material
4. deposited sediment and decomposed plant litter

answer:

I believe C or 3 is the correct answer; parent material is rich in nutrients for plants, and decomposed plant litter is also known as decaying organic material. Hope this helps! :)

it's unlikely a majority of a large population would agree on issues

hope this : )

"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."