Biology 5090 · O Level · Anaerobic respiration

Anaerobic respiration — practice question

Fitness training for athletes lowers the need for anaerobic respiration. It also increases the speed at which lactic acid is removed after exercise. The table gives the concentration of lactic acid in the blood of four different athletes. They exercise for 20 minutes and then rest for the following 70 minutes. The lactic acid concentration is measured in $\text{mg per }100\,\text{cm}^3$ of blood. Starting with the fittest athlete and ending with the least fit, which sequence is correct?

  • A$3 \rightarrow 2 \rightarrow 1 \rightarrow 4$
  • B$1 \rightarrow 2 \rightarrow 4 \rightarrow 3$
  • C$2 \rightarrow 3 \rightarrow 4 \rightarrow 1$
  • D$3 \rightarrow 1 \rightarrow 2 \rightarrow 4$

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