Why does a bean plant need light, water and air?
A bean plant uses light, water and carbon dioxide from the air to make food. It also needs oxygen for respiration.
- Start with what we can observe.
Leaves usually grow towards light. Roots take up water from the soil. A living plant also exchanges gases with the air.
- Explain how the needs connect.
Photosynthesis uses light energy, water and carbon dioxide to make sugars. These sugars help the plant grow.
- Remember that plants respire too.
Plants release energy from sugars through respiration, which uses oxygen. Plants respire in daytime and at night.
If light is missing, a plant cannot keep making food by photosynthesis. Giving extra water does not replace light.