A transparent flexible tube filled with water is used as a model of a vein. One end of the tube is labelled heart. Valve P is nearer to this end and valve Q is farther from it. A student squeezes the section of tube between the two valves. One of the valves is faulty.
| Valve | Observation when the section is squeezed |
|---|---|
| P | opens, and water moves through it towards the end labelled heart |
| Q | opens, and water moves through it away from the end labelled heart |
State which valve is faulty and explain how repairing it would affect the movement of water when the section is squeezed.
67 exam-style questions on Edexcel GCSE Biology 8.2 Blood and circulation, covering 8.2.1 Structure and function of the blood, 8.2.2 Structure of blood vessels, 8.2.3 Structure of the heart and circulatory system, and 8.2.4 Cardiac output. Each one has a worked solution and a mark scheme showing where the marks go.