Which One of the Following Statements About the Transport of Nutrients

Multiple Choice

Which one of the following statements about the transport of nutrients in phloem is correct?

A) Solute particles are actively transported from phloem at the source.
B) Companion cells control the rate and direction of movement of phloem sap.
C) Differences in osmotic concentration at the source and sink cause a hydrostatic pressure gradient to be formed.
D) A sink is the part of a plant where a particular solute is produced.