11.   More precisely, the scientists discovered that termites produce naphthalene, an aromatic hydrocarbon that is the major component of moth balls.

12.   McKay said the polycyclic aromatic hydrocarbons were the molecules critical to the life question and they were almost certainly from Mars, and were not products of contamination.

13.   Neither study examined one type of organic molecule, polycyclic aromatic hydrocarbons, found in easily detectable amounts in the meteorite.

14.   One clue was chemicals called polycyclic aromatic hydrocarbons or PAHs, which on Earth are sometimes generated by biological processes.

15.   Team member Richard Zare, a chemist at Stanford, used lasers and an extremely sensitive detector called a mass spectrometer to spot molecules called polycyclic aromatic hydrocarbons.

16.   The chemicals are called polycyclic aromatic hydrocarbons, or PAHs.

17.   The chemicals are technically known as polycyclic aromatic hydrocarbons.

18.   The debris, which also includes potentially carcinogenic polycyclic aromatic hydrocarbons, or PAHs, spews out the windows into the river.

19.   The smog is also heavily laced with polycyclic aromatic hydrocarbons, which are produced when organic materials, such as trees and undergrowth, are burned.

20.   Words like particulates, benzene and polycyclic aromatic hydrocarbons pop up in her speech.