Differential medium can separate gram negative bacteria from
grampositive bacteria.
true or false?

True. Selective media can be used to separate gram negative from gram positive bacteria.

Explanation: Selective media allow certain types of organisms to grow, and inhibit  the growth of other organisms.

For example: Media containing potassium  tellurite will  inhibit the growth of gram negative bacteria while media supplemented with penicillin will inhibit the growth of gram positive  bacteria.

the index of refraction of the second medium is higher. i just took the test trust me !