Biology I / The Colonisation of Land
Practice question · Multiple choice

A waterproof cuticle prevents desiccation on land but creates a barrier to atmospheric gases. How did plants resolve this trade-off without forfeiting water conservation?

Hints
  1. What structure must a leaf puncture to allow atmospheric carbon dioxide to enter?
  2. How can an organism maintain an impermeable barrier while still admitting necessary gases on demand?
Show the answer

A. They evolved regulated pores to balance gas diffusion and moisture loss

Why

Cuticles are impermeable barriers that solve desiccation but inevitably block direct gas diffusion; pores (stomata) provide an adjustable route for uptake. Confusing this with root respiration or non-existent permeable cuticles misses how structural trade-offs force active regulation.

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