Match column I with column II. Column I Column II 1. GHG (a) Paedogenesis 2. CFCs (b) Methane 3. PAN (c) Global warming 4. Lichen (d) Smog

1-b Greenhouse gases are those gases that absorb radiant energy within the thermal infrared range and emit heat in all directions. Methane is an example of it. 2-c Chlorofluorocarbons are nonflammable chemical compounds containing carbon, chlorine, and fluorine. They are used in the manufacture of aerosol sprays, foams, packing materials, and refrigerants. They are the major ozone-depleting substances that cause global warming. 3-d PAN or Peroxyacyl nitrates are powerful components of photochemical smog. It causes respiratory and eye irritation. They are formed in the atmosphere when oxidized organic compounds combine with nitrogen dioxide. 4-a Paedogenesis is a process in which biological agents like lichens and mosses that leads to the breakdown of rock into smaller particles by producing organic acids. Colum I Column II 1. GHG (b) Methane 2. CFCs (c) Global warming 3. PAN (d) Smog 4. Lichen (a) Paedogenesis