19. Suppose that some cells are grown in culture in the presence of radioactive nucleotides for many generations, so that both strands of every DNA molecule are radioactive. The cells are then harvested and placed in new medium with nucleotides that are not radioactive, so that newly synthesized DNA will not be radioactive. What proportion of DNA molecules will be radioactive after two rounds of replication

What best explains whether bromine (br) or neon (ne) is more likely to form a covalent bond? bromine forms covalent bonds because it has seven valence electrons, but neon has eight valence electrons and already fulfills the octet rule. bromine forms covalent bonds because it has many electron shells, but neon has only two electron shells and is tightly bound to its electrons. neon forms covalent bonds because it can share its valence electrons, but bromine has seven valence electrons and can gain only one more electron. neon forms covalent bonds because it has only two electron shells, but bromine has many electron shells and will lose electrons in order to fulfill the octet rule.

Producing disposable grocery bags consumes resources. recycling disposable bags is a solution that can recover some of the resources used to make new bags. which of the following behaviors could further refine the solution? a. disposing of bags by burning them b. reusing bags whenever possible c. using bags at once so that they do not break d. using only nonrenewable materials to make new bags subject is environmental science for apex users

During photosynthesis, hydrogen ions are most directly used to in the chloroplast pictured above. a) make glucose b) make chlorophyll c) produce carbon dioxide d) drive the production of atp