Question 1 · 1 mark · Difficulty 1/3
Which statement best defines diffusion?
- The net movement of particles from a region of their higher concentration to a region of their lower concentration down a concentration gradient
- The movement of particles from a region of lower concentration to a region of higher concentration using energy from respiration
- The net movement of particles from a region of lower concentration to a region of higher concentration down a concentration gradient
- The movement of water molecules from a region of high water potential to a region of low water potential through a partially permeable membrane
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✓ Answer: A — The net movement of particles from a region of their higher concentration to a region of their lower concentration down a concentration gradient
Award 1 mark for the correct definition. D is incorrect — this describes osmosis, not diffusion. B is incorrect because diffusion does not require energy from respiration; this describes active transport. C is incorrect because diffusion occurs from higher to lower concentration, not lower to higher.