The sick role is a term in Sociology, refering to <em>sickness</em> and the <em>rights and obligations</em> a sick individual has.
Parsons was a functionalist sociologist, meaning that all parts of society are important for its long-term development. When someone is sick, he/she is <em>no longer functional within the society </em>and thus has to be taken care of since it comes with a <em>"sanctioned deviance"</em> role.
All limestones contain at least a few percent other materials. These can be small particles of quartz, feldspar, clay minerals, pyrite, siderite, and other minerals.