In DSM, nicotine dependence is included under the general definition of substance dependence.  The essential feature of Substance Dependence is a cluster of cognitive, behavioral, and physiologic symptoms indicating that the individual continues use of the substance despite significant substance-related problems.
The Best Materials to Cover your Greenhouse. 1  Glass: The traditional greenhouse covering, glass is the preferred material for permanence. 2  Film Plastic: Film plastic is one sixth to one tenth of the cost per square foot of a glass covered structure.
In descending order, the gases that contribute most to the Earthâs greenhouse effect are: water vapour (H 2 O), carbon dioxide (CO 2), nitrous oxide (N 2 O), methane (CH 4) and ozone (O 3).