What percent of a sample of as-81 remains un-decayed after 43.2 seconds

Which layer will become saturated first when rain falls?

How can an organ, such as the lungs, work for multiple body systems?

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