An isolated colony on a selective medium is not considered a pure culture because inhibited organisms might be masked by the colonies. This statement is true.
On the basis of their constitution or usage, culture media can be classified into various groups; these include defined, complex, selective, as well as enrichment medium. 
A selective medium consists of dyes or noxious substances/chemicals which inhibit the growth of specific microorganisms but promote the growth of other microbes.
A pure culture is a laboratory culture which contains a single species of microorganism. It is free from other microorganisms.
Since selective media affects the growth of distinct organisms differently, therefore, an isolated colony formed in such type of medium is not considered a pure culture.
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The answer is; Warm water moves to the east instead of to the west
Normally, when the waters in the Pacific warm up, the prevailing winds that blow from east to west drag the warm surface currents westwards and upwelling of cold currents occur at the west coast of South America. However, in El Nino, the Pacific ocean waters heat more than usual. The prevailing winds weaken and begin to blow predominantly towards the east. The warm currents are therefore dragged to the east and cause torrential rains in Western coast South Americas. 
 
        
                    
             
        
        
        
If you used a full active virus, that defeats the point of a vaccine. You will trigger your immune response, but since you would just be injecting the virus, it will make you sick, and your body will be less effective at fighting the pathogens. 
Viruses in vaccines are weakened, so they essentially will not "fight" back. They most importantly just contains the antigen markers so the body can trigger the immune response, quickly eradicate the pathogen, and build up the memory cells to that virus. 
Injecting a virus that is not weak will just be the same thing as if you got the virus, you will likely get sick. 
 
        
             
        
        
        
Glacial lakes are bodies of water that are influenced by the presence of glaciers. ... Glacial lakes are common features around the margins of glaciers and ice sheets, and often evolve from ice-contact lakes into ice-distal lakes as glaciers and ice sheets margins retreat and become spatially separated from the lake.