Killing insects with low oxygen. A group of Australian entomological toxicologists investigated the impact of exposure to low oxygen on the mortality of insects (Journal of Agricultural, Biological, and Environmental Statistics, Sept. 2000). Thousands of adult rice weevils were placed in a chamber filled with wheat grain, and the chamber was exposed to nitrogen gas for 4 days. Insects were assessed as dead or alive 24 hours after exposure. At the conclusion of the experiment, 31,386 weevils were dead and 35 weevils were found alive. Previous studies had shown a 99% mortality rate in adult rice weevils exposed to carbon dioxide for 4 days. What advice would you give to the entomologists regarding the use of nitrogen or carbon dioxide for killing rice weevils?