Which of the following is a true statement about ozone?

a. It's helpful when it's located in the upper atmosphere, but harmful when people breathe it

b. It's harmful when it's located in the upper atmosphere, but helpful when people breathe it

c. It's always helpful

d. It's always harmful

What re the two main phrases of the cell cycle.

Which of the following matches the organisms described with the correct domain? a. bacteria--unicellular, eukaryotic organisms with cell walls that do not contain peptidoglycanb. archaea--multicellular, eukaryotic organisms that do not have cell wallsc. eukarya--single-celled and multicellular organisms, with a defined nucleus and a variety of nutritional sourcesd. bacteria--unicellular, eukaryotic organisms that always lack cell walls

How does the nervous system affect the excretory system?