9 Exercise causes changes in the circulation of the blood - Edexcel - GCSE Biology - Question 9 - 2021 - Paper 1

To calculate the percentage change in blood flow to the stomach, use the following formula:

ext{Percentage Change} = rac{ ext{New Value} - ext{Old Value}}{ ext{Old Value}} imes 100

1. Identify the blood flow values:

   • Blood flow at rest (Old Value): 500 cm³/min (from Figure 13)
   • Blood flow during exercise (New Value): 200 cm³/min (from Figure 13)

2. Apply values to the formula:

   ext{Percentage Change} = rac{200 - 500}{500} imes 100

3. **Calculate the change**: - $$200 - 500 = -300$$ - $$ ext{Percentage Change} = rac{-300}{500} imes 100 = -60 ext{%}$$ 4. **Conclusion**: The blood flow to the stomach decreases by approximately 60% during exercise.