Symplast Pathway Relies on Membrane Regulation

Steps:

• Define symplast as interconnected cytoplasm via plasmodesmata for solute movement.
• Identify entry point: solutes cross plasma membranes selectively into root cells.
• Evaluate options: A matches membrane control; others misstate connections or barriers.
• Confirm A via plant transport biology.

Why A is correct:

• Symplast transport begins with selective permeation across plasma membranes, regulating solute absorption per cell membrane function.

Why the others are wrong:

• B: Plasmodesmata link symplast cells, not control exit to apoplast (cell walls).
• C: Incomplete and inaccurate; symplast transports all dissolved minerals, no "cannot be" restriction.
• D: Endodermis forces symplast use via Casparian strip but allows plasmodesmata passage.

Final answer: A