# A farmer keeps her tomato plants in a greenhouse. During winter, the farmer notices that the rate of photosynthesis in her tomato plants is much lower than in summer. Explain why the rate of photosynthesis is lower in winter, and describe TWO ways the farmer could increase the rate of photosynthesis in her greenhouse during winter.

> Edexcel GCSE Biology (1BI0) — 6.1 Photosynthesis · Explain · 4 marks

## Mark scheme (4 marks)

1. Light intensity is lower in winter (fewer daylight hours / less sunlight), so light is a limiting factor that reduces the rate of photosynthesis.
2. Temperature is lower in winter, so temperature acts as a limiting factor reducing the rate of photosynthesis.
3. The farmer could add artificial lighting to the greenhouse to increase light intensity.
4. The farmer could heat the greenhouse to increase temperature, removing temperature as a limiting factor.

## Key terms

- [photosynthesis](https://www.gradenine.co.uk/glossary/photosynthesis)

## Related

- [Revision notes for Edexcel GCSE Biology (1BI0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-farmer-keeps-her-tomato-plants-b0c88360) · Published by Druglandscape Ltd.