- You are provided with specimen G.
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- Cut off the petiole, about 1.5 cm from the end where the leaf attaches to the stem.
- Carefully make several thin cross sections through the piece obtained in (a)(i) above, using a sharp razor blade or scalpel.
- Put the sections obtained in water on a Petri dish.
- Mount the thinnest section(s) on a glass slide, add a drop of iodine solution provided.
- Observe the section(s) using a hand lens, then draw a labelled diagram of the section observed(3 marks)
- Account for the following features of specimen G.
- Extensive network of veins(1 mark)
- Tough leaf blade(1 mark)
- Strong and extended petiole(1 mark)
- State with reasons, the class of plants from which the specimen was obtained
Class.(1 mark)
Reasons:(3 marks) - Explain why the following procedures were necessary during the preparation of the sections for observation
- Putting the sections in water on a Petri dish.(1 mark)
- Using a sharp scapel/razor blade.(1 mark)
- Adding iodine solution to the section.(1 mark)
- Cutting very thin sections.(1 mark)
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- Study the photograph below of some animals in a certain ecosystem and answer the questions that follow.
- State the type of biotic relationship exhibited by the animals shown in the photograph.(1 mark)
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- Identify which of the two animals, E and F, will have the least biomas?(1 mark)
- Give a reason for your answer in (b)(i) above.(2 marks)
- Explain the concept of "Survival for the fittest" in relation to the organisms illustrated in the photograph(3 marks)
- Explain three visible survival adaptive features for the organisms illustrated in the photograph(6 marks)
- The photograph below illustrates a procedure carried out to study gaseous exchange structures in a certain organism.
- Identify two dissecting tools being used in the procedure illustrated.(2 marks)
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- Name the class of the animal in use.(1 mark)
- State any two visible characteristics from the photograph to support your answer in (b)(i) above.(2 marks)
- Name the part of the organism labelled H and state its function
Name:(1 mark)
Function.(1 mark) -
- Draw the gaseous exchange structure under study and on it, label the site for gaseous exchange.(3 marks)
- How is the part labelled in (d)) adapted to efficient gascous exchange?(3 marks)
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