question-1
(i) State the function of human teeth.
To help in mechanical (physical) digestion
(ii) State the name of the visible outer layer of the teeth.
enamel
(iii) Explain the process of tooth decay in humans.
Any three from the mark scheme:
- The sugar from the food is left on teeth. The respiration of sugar by bacteria produces lactic acid. This lactic acid dissolves enamel (dentine) and causes tooth decay.
question-2
(i) State the name of the process by which leafy shoots lose water.
transpiration
(ii) Before the leafy shoot is inserted into the jar shown in Fig. 3.1, it must be recut under water. Suggest why the end of the leafy shoot was cut under water.
To ensure continuous column of water or prevents air bubbles or prevents airlock.
(iii) State the purpose of the oil layer on top of the water in the burette.
To prevent evaporation or condensation from the top of the burette affecting the volume of water in the burette.
(iv) Using the information in Fig. 3.1, describe one method that can be used to determine how much water is lost from the leafy shoot.
Measure the decrease in the volume of water in burette over a period of time or record the decrease in mass over time.
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