A student carried out the following investigation: she placed a leafy plant into a flask with water and covered the water surface with a layer of oil. She then placed the flask on top of a balance to weigh it.

1. aState the aim of the investigation. [1]
2. bWhat will happen to the reading on the balance when the plant is exposed to higher temperature? [1]
3. cWhat is the purpose of the oil layer in the investigation? [1]

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