(i) Transpiration: Loss of water as water vapour from aerial parts of the plant.
(ii) After 2-3 days the level of water falls in test-tube A while it remains constant in test tube B.
(iii) The fall in the level of water in test-tube A due to the absorption of water by the roots.
(iv) The oil has been put in each test-tube to prevent the loss of water by evaporation.
(v) The purpose of setting up test-tube B is to show that in the absence of plant, there is no change in the level of water.