An ultra-endurance athlete running in an arid environment experiences severe dehydration, leading to a marked decrease in the water potential of their blood plasma.
Describe the physiological mechanisms by which the body detects and responds to this change to restore the water potential of the blood back to its homeostatic norm.
Explain the physical effect of this untreated, low blood water potential on the red blood cells circulating in the plasma.
17 exam-style questions on Edexcel IGCSE Biology Excretion. Each one has a worked solution and a mark scheme showing where the marks go.