Oil palm trees produce a greater oil yield than other oil-producing plants. Fig. 8.1 presents the oil yield of four crop plants. Calculate how many hectares of soya bean plants would be required to produce the same amount of oil as one hectare of oil palm trees. Show your working and give your answer to one decimal place. Oil yield is measured in $\text{kg ha}^{-1}\text{ yr}^{-1}$.
Rainforests have been cleared in Malaysia and Indonesia to create oil palm plantations. This lowers biodiversity. Outline reasons why biodiversity is important to maintain.
Palm oil companies are now being expected to produce palm oil sustainably. This means that no further deforestation should occur. Suggest ways in which individual consumers can encourage manufacturers to use palm oil from sustainable sources.