Food: wheat, rice, potatoes
Cloth and fibre: cotton, hemp, flax
Building material: pine, bamboo, bulrushes
Fuel: wood, coal, peat
Medicine: quinine for malaria, calendula (marigold) for inflammation, clove oil for toothache

2. Oxygen; it will re-light a glowing splint
3. The plant makes oxygen, which the candle needs to burn. Repeat the experiments to make the results more reliable.
4. Plants make oxygen that animals need for respiration.
5. Yes. The heater makes carbon dioxide as well as warming the greenhouse.
6. Starch is present. Potatoes store starch for next year’s growth.
7. Nitrate (nitrogen) - to make protein and DNA, phosphate (phosphorous) - to help release energy, to make protein and DNA, potash (potassium) - to move substances in and out of cells
8. They are all right. Plants need carbon dioxide and water to make wood. They also need minerals from the soil.
9. The bubbles come out of small pores called stomata. They are only found on the lower surface of the leaf, which is shaded from the sun and protected from wind. This stops the leaf drying out.
10. There is more chlorophyll on the upper surface because there is more light.