Genetically modified Papaya
About 60% of the papaya grown in the United States, all in Hawaii, have been genetically engineered to allow it to withstand the ringspot virus. Several countries, including Japan and South Korea, distrust anything that is genetically modified and have banned the importation of them.
#5 cost of removal disposed chewing gum tens and hundreds of millions annually, so...
#3 ketchup has no room in schools, however you look at it.