AIDS is caused by the human immunodeficiency virus, or HIV. By killing or damaging cells of the body's immune system, HIV progressively destroys the body's ability to fight infections and certain cancers.People diagnosed with AIDS may get life-threatening diseases called opportunistic infections.IDS is caused by the human immunodeficiency virus, or HIV. By killing or damaging cells of the body's immune system, HIV progressively destroys the body's ability to fight infections and certain cancers.
Blackboard Learn (previously the Blackboard Learning Management System), is a virtual learning environment and course management system developed by Blackboard Inc.
(April 2008). A quadruple blackboard at the Helsinki University of Technology. A blackboard (UK English) or chalkboard (US English; also blackboard) is a reusable writing surface on which text or drawings are made with sticks of calcium sulfate or calcium carbonate, known, when used for this purpose, as chalk.ticks of processed chalk are produced especially for use with blackboards in white and also in various colours. These are often made not from chalk rock but from calcium sulfate in its dihydrate form, CaSO 4 Â·2H 2 O (gypsum). Chalk sticks containing calcium carbonate typically contain 40-60% of CaCO 3 (calcite).