553/2

BIOLOGY

Paper 2

2024 2 ½ HOURS

        YAAKA EXAMINATIONS

                             BIOLOGY

                            Paper 2

INSTRUCTIONS TO CANDIDATES

This paper consists of two examination items. Answer all the items in the spaces provided.

Drawings should be made in the spaces provided. Use sharp pencils for your drawings. Coloured pencils or crayons should not be used.

No additional sheets of writing paper are to be inserted in the booklet. Work on additional sheets will not be scored.

INSTRUCTIONS FOR PREPARING SPECIMENS AND APPARATUS

The teacher responsible for preparing specimens must ensure that candidates are provided with correct specimens and other materials as specified in these instructions. Specimens and solutions which have been assigned codes should be presented to candidates using those codes only and not any other identity. The head teacher must ensure that the teacher responsible for preparing the specimens hands in his/her trial results for the physiology/biochemistry question, properly sealed in a separate envelope and firmly fastened (attached) to the candidates’ script envelope(s).

In addition to the apparatus ordinarily contained in a Biology Laboratory, each candidate will require;

          Specimen A: Mixture of sand and clay soil in a ratio of 1:1.

• Specimen B: Mixture of sandy soil and loam soil in a ratio of 2:1.
• Specimen C: Freshly killed housefly.
• Specimen D: Freshly killed grasshopper.
• Specimen E: Freshly killed honeybee.

Materials Needed:

• 50 cm³ measuring cylinders.
• pH indicator strips.
• Distilled water for testing.
• Hand lens.

Special Notes:

• Specimens should be labeled only with their assigned codes.
• Ensure proper disposal of the killed specimens after the exam.

Item 1

A farmer is considering planting maize and requires suitable soil. You are provided with soil samples A and B. Design and conduct an investigation to determine which soil is most suitable for maize planting, focusing on texture, water retention, and pH.

Task:

(a). Describe the methods used for testing the soil samples.

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(b). Record observations and draw conclusions about the suitability of each soil sample. 

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Item 2

Insects play different roles in the garden ecosystem. You are provided with specimens C, D, and E. Use the provided materials to study and identify each insect’s role.

Task:

(a). Construct a dichotomous key to identify specimens C, D, and E.

(b). Explain the ecological role of the beneficial insect identified.

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(c). Draw and label the key features of the beneficial insect’s hind limb.