Based on cell theory, why is a virus considered non-living? a) a virus does not have a nucleus. b) a virus does not contain genetic material. c) a virus is too small to be considered a cell. d) a virus cannot reproduce itself without a host cell.

Which of these is an example of land degradation? a. containers designed to store pollutants leak. b. fertilizers provide too many nutrients to crops. c. garbage is buried so the land can be reclaimed later. d. a drought kills all the plants in an area, leaving bare land

Scientific evidence is most likely to be consistent if it is based on data from

Which of the following is a reason why early living organisms on earth could not have survived on the surface? 1. the lack of an ozone layer 2. the lack of oxygen in the atmosphere 3. the fact that these organisms were single-celled