If a person is to survive, the internal environment of their body must be controlled - Edexcel - GCSE Biology - Question 4 - 2012 - Paper 1

The mean volume of urine produced on the cold day can be calculated as follows:

From the table:

• Person 1: 890 cm³
• Person 2: 1060 cm³
• Person 3: 930 cm³
• Person 4: 1280 cm³
• Person 5: 680 cm³
• Person 6: 1160 cm³

Summing these values:

$890 + 1060 + 930 + 1280 + 680 + 1160 = 5000 \text{ cm}^3$

Now, dividing by the number of persons:

$\text{Mean} = \frac{5000}{6} \approx 833.33 \text{ cm}^3$

The difference in mean volumes:

$833.33 - 400 = 433.33 \text{ cm}^3$

Thus, the difference between the mean volumes on the hot and cold days is approximately 433.33 cm³.

The body regulates water levels to maintain homeostasis. This involves:

• Water lost via sweating to cool the body during hot conditions.
• Sweating more when engaging in physical activity to prevent overheating.
• Maintaining adequate hydration levels to ensure proper physiological functions.