In the dna helix, which part of the nucleotide forms the sides of the ladder, the backbone? a. pentose sugar and nitrogen base b. pentose sugar and phosphate group c. nitrogen base and carboxylic acid d. phosphate group and carboxylic acid

What is thought to have caused the mass extinction at the end of the cretaceous period?

Which would best keep the oxygen cycle stable? a. cutting down jungles to create farmland b. eliminating parks in large cities c. dumping toxic chemicals into the ocean d. reducing the amount of deforestation d. reducing the amount of deforestation

The human genome project is devoted to mapping the general dna sequence of our species. this could lead to the development of new medicines, as well as the possibility of using gene therapy to treat certain diseases. however, there are some ethical issues surrounding the mapping of individual genomes. one concern is a) that your genes may change over time, making the project useless. b) that insurance companies could discriminate based on genetic make-up. c) that since this has never been done before, we should probably not do it now. d) that sequencing our individual genomes is so expensive, it is a counter-productive strategy.