The incorrect statement is: C) It transports mainly sugars and amino acids.
Xylem together with floem is a plant tissue involved in the transport of substances through the plant.
Xylem’s role is to transport water (sometimes and nutrients) from roots to stems and leaves and to provide support to the plant. Xylem consists of a specialized, water-conducting cells - tracheary elements (tracheids and vessel) which are long, narrow and hollow.
If a bacterium cannot use citrate agar will not change its color (stays green). On the other hand, if bacteria have the ability to use citrate, the medium will change its color from green to blue.
This happens because citrate agar contains pH indicator such as bromothymol blue which transforms from green to blue in alkaline conditions.
There is no definite amount that is why it is also called multiple gene inheritance