What is the medium in bottom picture? Is selective ... Why? What does it grow? Is differential ...Why? What does the differential property reveal about the bacteria growing there? Solution The medium in bottom pictures a gel made up of agar. It is a selective & differential media. It is a selective because the agar plate in this in the diagram shows that only specific bacteria can be grown and resist the growth of all other bacterial species. EXAMPLE: Mannitol sat agar, Mac conkey agar, Eosin mythylene blue agar etc..... It grows Staphylococcus aureus. USES:-Differential media is used to check water pollution, diary industries and in medical science . The differential property reveal that the bacteria grow there is mainly Escherichia coli. It can be used to know the amount of bacterial colonies present in water, air etc....,.