Official approaches to squatter settlements and the housing of the urban poor have changed over time from policies of clearance and relocation to schemes which promote the involvement of the private sector and nongovernmental organizations in supporting poor residents to improve their own housing and neighborhoods.n this article, the main debates surrounding squatter settlements are outlined, focusing on definitional issues and their geographical distribution. The changing nature of policies toward these settlements is also covered.
Lichen. Lichen is a structure that commonly grows on trees; it is a result of a symbiotic relationship between algae and fungi. The fungus provides a structure that collects water and nutrients that the algae takes advantage of; the algae in turn uses its chlorophyll to produce food for both itself and the fungus.Species of the Trentepohlia genus are commonly found in lichens.he fungus provides a structure that collects water and nutrients that the algae takes advantage of; the algae in turn uses its chlorophyll to produce food for both itself and the fungus. Species of the Trentepohlia genus are commonly found in lichens.
In laboratory settings, algae grow faster when they are alone rather than when they are part of a lichen. But there is also a mutualism side to the relationship, the fungus part of the lichen provides the alga with water and minerals that the fungus absorbs from whatever the lichen is growing on.he lichen fungus is typically a member of the Ascomycotaârarely a member of the Basidiomycota. Some lichen taxonomists place lichens in their own division, the Mycophycophyta, but this practice ignores the fact that the components belong to separate lineages.