Net movement follows concentration gradients via diffusion

Steps:

• Identify the process: Net movement across a membrane occurs through simple diffusion, driven by concentration gradients.
• Evaluate statement 1: It likely claims movement against the gradient, which requires active transport, not net passive movement.
• Evaluate statement 2: This describes movement from high to low concentration until equilibrium, correct for diffusion.
• Evaluate statement 3: This notes no net movement at equilibrium, also correct as concentrations equalize.

Why C is correct:

• Statements 2 and 3 align with Fick's law of diffusion, where net flux is proportional to the gradient and stops at equilibrium.

Why the others are wrong:

• A includes incorrect statement 1, ignoring active transport distinction.
• B pairs wrong 1 with correct 3, missing 2's gradient description.
• D includes all, but 1 misrepresents passive net movement.

Not enough information on exact statements, but based on standard membrane diffusion principles.

Final answer: C