Why do larger organisms need specialised exchange surfaces and mass transport systems?
Answer and explanation
Correct answer: C. Their surface area to volume ratio is too small for diffusion alone to meet their needs
- Step 1: As organisms grow, volume increases faster than surface area. Step 2. Diffusion distances become too long to supply all cells. Answer: Their surface area to volume ratio is too small for diffusion alone to meet their needs. Why not the others: cell size is similar between large and small animals; smaller animals have higher metabolic rate per gram; diffusion does occur across membranes.
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