Isolation

To obtain a pure culture from a mix culture

It is a visible mass of cells produced on culture media from a single cell or single CFU(colony forming unit)

Because colony can be form by 1 cell or many cell so we just call 1 of those mass as a unit that form colony

• Allow to get individual colonies, and does not require serial dilution.
• the disadvantage is that you can't quantify bacteria

to get individual colonies, good for quantification, and accompanied by serial dilution

Anywhere away from the streak or if they have different morphologies

A media that inhibits or suppresses unwanted microbes but favors and encourages the growth of desired microbes

• Substances or indicators built in the media that allow to distinguish certain type of bacteria. 
• Allow multiple type of bacteria to grow but only the wanted one are visible