10 free IB Biology practice questions in the real exam format, covering the official content areas, with an explanation for every answer.
IB Biology Practice Test 12Tutor mode
Question 1 of 10
Form and function
Method. Six volunteers aged 16–18 cycled on an exercise bicycle at a constant power output of 100 W for 8 minutes. A spirometer was used to measure ventilation rate and tidal volume at rest (0 min) and every 2 minutes during the exercise. The table shows the mean and standard deviation for the six volunteers.
Ventilation during exercise at 100 W
Time / min
Ventilation rate / breaths min⁻¹
Tidal volume / dm³
0 (rest)
14 ± 2
0.50 ± 0.06
2
22 ± 3
1.20 ± 0.15
4
26 ± 3
1.55 ± 0.18
6
28 ± 4
1.70 ± 0.20
8
29 ± 4
1.75 ± 0.21
Values are mean ± SD, n = 6.
Which statement describes the trend in tidal volume during the exercise?