<prompt> Rebreathing systems are WETo fro systemCircle systemWaters systemMapleson F  <response>: D i.e. Mapleson F - Calcium hydroxide is the main component of both sodalime 94 and baralimeQ 80. - BaOH2 is not a constituent of soda lime, it is used in baralime. Water of crystalization is used to produce hardening in baralimeQ. - Clayton, mimosaQ, ethyl violet, phenolphthalein ethyl orange are indicators. 