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KCSE CLUSTER TESTS 20

Biology Paper 3

1.

You are provided with solutions X, Y and Z. Z is the same as Y except that Z has been boiled.

Label three test-tubes A, B and C. Into the test-tube labeled A add 1ml of solution X Into the test –tube B add 1ml of X and 1ml of Y Into the test-tube labeled C add 1ml of X and 1ml of Z

a) Withdraw a drop from test-tube A and place it on a white tile.

To the drop add one drop of iodine solution. Record your observations in the table below.

Repeat the procedure with contents in test –tubes B and C. Record your observations in the table. Place the three test-tubes labeled A, B and C into a water bath at 370C.


Ensure that the temperature of the water bath neither falls below 350C nor exceeds 380C. Leave the set up for about 30 minutes.


b) After 30 minutes, test the contents of each of the test-tubes labeled A, B and C following procedures in (a) above. Record your observations in the table below.

c) Account for the results at the end of the experiment in the test tube labeled.

i) B

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ii) C

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d)

i) Suggest the identity of solution Y.

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ii) Give three reasons for your answer in (d) (i) above.

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14 marks

2.

Study the photographs attached and titled ‘photographs for question 2’ carefully and answer the questions that follow.

a)

i) Identify the kingdom to which organisms shown in A and B belong. Kingdom

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ii) Give a reason for your answer in

a)

i) above (1mk)

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b) i) Name the structures labeled E

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ii) State the function of structures labeled E

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iii) Identify the mode of reproduction as shown in A above.

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c) State one economic importance of the organisms in the Kingdom mentioned in a) i) above. (1mk)

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d)

i) Identify the Phylum to which organisms C and D belong (1mk)

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ii) Using observable features state two reasons for your answer in d) i)

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e) Name the body segment labeled F.

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f) Using observable features, name the class to which organisms C and D belong giving one reason in each case.

C class

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Reason

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D class

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Reason

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12 marks

3.

Photographs J and K1 attached and titled ‘photographs for question 3’, represent specimens which were obtained from different habitats. K2 represents the features of the stem of K1.

a) With reasons, identify the habitat where each specimen is found.

Habitat for J

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Reason

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Habitat for K1

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Reason

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Describe the observable features which adapt specimen K1 to its habitat. ...........................................................................................................................................................................................................................................................

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b) State the significance of the numerous leaves in specimen J. ...........................................................................................................................................................................................................................................................

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c) Suggest expected differences between root systems of specimen J and K1 ...........................................................................................................................................................................................................................................................

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d) Give the term used to describe plants found in the same habitat with specimen K1. (1mk) ...........................................................................................................................................................................................................................................................

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14 marks

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