Solute concentration changes via membrane transport mechanisms

Steps:

• Examine graph for phases of increasing/decreasing solute concentration inside cell.
• Match labels: 1 (initial influx via diffusion), 2 (water movement, irrelevant to solute), 3 (active transport buildup), 4 (facilitated diffusion equilibrium).
• Eliminate 2 as it describes osmosis, not solute transport.
• Combine 1, 3, 4 to explain full concentration dynamics from passive to active to balanced movement.

Why B is correct:

• B selects 1, 3, and 4, aligning with diffusion (passive per Fick's law), active transport (ATP-driven against gradient), and facilitated diffusion (carrier-mediated), fully accounting for observed changes.

Why the others are wrong:

• A includes 2 (osmosis affects water, not solute concentration directly).
• C omits 3, ignoring energy-dependent active transport phase.
• D omits 1, excluding initial simple diffusion influx.

Final answer: B