The development factored into the development of complex organisms.

ozone
oxygen
cyanobacteria
all of the above

the end of the paleozoic era was signaled

the development of humans
mass extinction of land and sea animals
the development of organisms with hard parts
both a and b

reptiles evolved from an ancestor of amphibians that developed a(

egg with a strong outer shell that kept it from drying out
hard set of teeth
thick eyelid
long tail

answer'(basidium)the spore--bearing structure of a basidiomycete is called a basidiocarp; ///

"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."