Question Constellation Sign up for free AQA · GCSE · Biology · Higher
Greenhouse heating trade-offs
A person grows tomatoes in a greenhouse. The mean temperature of the greenhouse is 15 °C. A heater would keep the temperature of the greenhouse at 25 °C.
Suggest two reasons against using a heater set at 25 °C in the greenhouse. Do not refer to cost in your answer.
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Marking points
- 1 Identifies a possible glut or too many tomatoes to eat/sell.
- 2 Explains that another factor could limit photosynthesis or tomato production.
- 3 Questions whether 25 °C is the optimum temperature.
- 4 Identifies poor greenhouse insulation.
- 5 Identifies pollution, carbon dioxide emissions, or global warming.
- 6 Identifies increased transpiration or plant water loss.
- 7 Identifies increased spread of plant disease.
Full-mark answer
At 25 °C another factor such as light intensity or carbon dioxide concentration could still limit photosynthesis, so heating may not increase yield. The higher temperature could also increase transpiration and water loss from the tomato plants.
Why this answer loses marks
The heater would cost too much.
The task excludes cost, so use distinct biological, production, or environmental drawbacks of heating the greenhouse.