In phloem transport, what is the role of a sink?

• A. Transports water to roots
• B. Uses or stores sugars
• C. Produces sugars for transport
• D. Picks up nutrients from soil

Answer: (B)

In phloem transport, a sink is a tissue that uses or stores sugars produced by photosynthesis. Sugars are loaded into the phloem at a source, creating a flow toward areas where they’re needed. When the sap reaches a sink, the sugars are unloaded and then used for growth and metabolism or stored as starch. This consumption or storage keeps the flow moving from source to sink. The other ideas—producing sugars, transporting water, or taking up nutrients from soil—don’t describe the sink’s role in this process.