Biology 9700 · 14 Homeostasis
14.2 Homeostasis in plants
Explain how guard cells regulate stomatal aperture in response to environmental conditions, including the role of abscisic acid.
- Questions
- 42
- Years
- 2004–2026
- Multiple choice
- 8
- Written answer
- 34
- Average marks
- 10.8
Where this subtopic appears
- Paper 4variants 04, 41, 42, 4319
- Paper 1variants 01, 11, 12, 138
- Paper 2variants 02, 22, 236
- Paper 5variants 05, 51, 52, 536
- Paper 3variants 32, 333
Questions by year
| Year | Feb/March | May/June | Oct/Nov | Total |
|---|---|---|---|---|
| 2026 | 1 | 1 | – | 2 |
| 2023 | 1 | – | 3 | 4 |
| 2022 | 1 | 2 | – | 3 |
| 2021 | – | 1 | 3 | 4 |
| 2020 | – | – | 3 | 3 |
| 2019 | 1 | – | 2 | 3 |
| 2018 | – | – | 2 | 2 |
| 2017 | 1 | 1 | 1 | 3 |
| 2016 | – | – | 5 | 5 |
| 2015 | – | 2 | 1 | 3 |
| 2011 | – | 4 | – | 4 |
| 2010 | – | – | 1 | 1 |
| 2008 | – | – | 2 | 2 |
| 2005 | – | – | 1 | 1 |
| 2004 | – | 1 | 1 | 2 |
