• Type in the correct tense of the verb in the spaces.
  • Click the button at the bottom to check your answers.
  • Press the "refresh" button on your browser to play again.

discover be conduct find be say form show derive call
analyse look track come include travel be conclude be affect
Scientists have what they believe to the cleanest air on Earth. Researchers from Colorado State University and the Australian Bureau of Meteorology research on the purity of the air above Antarctica. They a region over the Southern Ocean, between the south of Australia and Antarctica, that "unaffected" by human activity. The scientists the area they researched the atmosphere in the lower clouds. The analysis of the air that it was totally free from "anthropogenic aerosols". These are pollutants or particles from human activity, or dust from other continents. The scientists this pollution-free area, "truly pristine".

The scientists the structure of airborne microbes in the lower clouds over the Southern Ocean. They at the DNA of the microbes and where they from. Their analysis monitoring wind trajectories to detect how far the microbes may have . They found that the atmospheric eco-system was very much "isolated," self-contained, and free from contaminants from elsewhere in the world. The source of the microbes the Southern Ocean, rather than airborne pollutants from other continents. The researchers that the Southern Ocean one of very few places on Earth that has been "minimally by anthropogenic activities."

Back to the clean air lesson.

Share this lesson

More Free Sites by Sean Banville

Online Activities