KCSE Mokasa Biology Joint Exams and Marking Schemes Free Access

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BIOLOGY PAPER 3

(Theory)

Time: 1 hours 45 minutes

MOKASA II JOINT EVALUTION EXAMINATION

Kenya Certificate of Secondary Education

• Write your name, Index Number in the spaces provided above.
• Write the date of examination in the space provided above.
• Answer ALL the questions in the spaces provided below each question in the question paper.

FOR EXAMINER’S USE ONLY

1. Solution A and B are mammalian excretory products. They are similar except they were obtained from two different animals ;A and B of the same species. This is the main nitrogenous waste in mammals

Use the two samples A and B to carry out the following experiment and hence record your findings.

Using the reagents provided,Carry out the appropriate food tests on sample A and B and hence complete the table below.(6mks)

(b) With reference to the results suggest the animal that is unhealthy. (1mk)

1. c) For the unhealthy (sick) animal identified in (b) above, name the disease its suffering from. (1mk)

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1. d) Explain the cause of the disease identified in (c) above.      (2mk)

1. e) State how the disease in (c) above can be treated. (1mk)

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(f) Other than excretory wastes  in A and B, name any  other nitrogenous excretory wastes in animals and give an example of an animal that excretes it.                                                            (2mks)

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2. Observe the photographs below and answer the questions that follow.

1. a) Name the feeding relationship illustrated in Photograph:

T…………………………………………………………………………… (1MK)

Y……………………………………………………………………………. (1mk)

1. b) With reasons identify the phylum and the kingdom to which organism S belongs

1. c) State two observable roles of organism P to an ecosystem in photograph T (2MK)

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1. d) State the significance of the behavior pattern illustrated by
2. I) Organism in photograph U (IMK)

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1. II) Organism in photograph Z (1mk)

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1. e) Organism S and organism Z initially belonged to the same species but with time they have speciated to two distint species. Explain the mechanism that has led to their speciation (2mks)

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1. f) Explain why we can only have a limited number of tropic levels in a natural ecosystem (1mk)

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3. Below are photographs of mammalian bones J, R, A and B from the same animal.

1. With reasons identify the following bones. (4mk)

1. Onto which of the labelled parts on J does structure 1 and 2 on bone R articulate. (2mk)
2. 1 articulates with. ……………………………………….
3. 2 articulates with. ……………………………………….
4. Make a drawing to show how bones J and bone R articulate (3mk)

1. Name the bone that articulates with Bone A at the proximal and name the type of joint formed. (2mks)

1. Name the region from which bone B was obtained. (1mk)

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1. State two ways in which bone B is structurally adapted to perform its functions. (2mk)

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