A-Level Biology OCR A H420

Paper 1 - Jun 2018 H420/01

Time allowed: 2 h 15 min.

The total mark for this paper is 100.

The marks for each question are shown in brackets [ ].

1.
Which of the following statements, A to D, correctly explains a feature of an efficient gaseous exchange surface?

A - The layers are thin for a short diffusion distance.

B - There is a good blood supply, so the system reaches equilibrium quickly.

C - There is an increased surface area to reduce surface area to volume ratio.

D - Ventilation takes place to reduce concentration gradient of dissolved gases.
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END OF QUESTION PAPER
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