Common indoor plants may prove to be a valuable weapon in the fight toward rising levels of indoor air pollution. Those 1. ______ plants in your office or home are not only decoratively, but NASA 2. ______ scientists are finding them to be surprisingly useful in absorbing potentially harmful gases and clean the air inside modem 3. ______ buildings. NASA and the Associated Landscape Contractors of America (ALCA) have announced the findings of a 2-year study that suggest the normal indoor plant may provide a natural way of 4. ______ helping combat with "Sick Building Syndrome". 5. ______ Research into the use of biological processes as a mean of 6. ______ solving environmental problems, both on Earth and in space habitats, have been carried out for many years by Dr. Bill 7. ______ Wolverton, former a senior research scientist at NASA’s John C. 8. ______ Stennis Space Center, Bay St. Louis, Miss. Based on preliminary evaluations of the use of common indoor plants for indoor air purification and revitalization, ALCA enjoyed NASA to fund a study using about a dozen popular 9. ______ varieties of ornamental plants to determine their effectiveness in removing several key pollutants associated with indoor air pollution. NASA research on indoor plants has found while living 10. ______ plants are so efficient at absorbing contaminants (污染物) in the air that some will be launched into space as part of the biological life support system aboard future orbiting space stations.