a) What is a dichotomous key? (1mk)
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b) Name the gaseous exchange structures of the following organisms. (2mks)
i) Crustacea
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ii) Arachnida
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An organism was found to have the following dental formula.

a) Calculate the total number of teeth of the organism. (2 mks)
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b) With a reason suggest the mode of feeding of the organism from which the dental formula was
obtained (2mks)
Mode of
feeding…………………………………………………………………………………………
Reason
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State one economic importance of each of the following excretory products. (3mks)
a) Colchicine
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b) Nicotine
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c) Quinine
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The diagram below shows a transverse section of a plant organ

a) Name the plant organ from which the section was obtained. (1mk)
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b) i) Name the class to which the plant organ was obtained. (1mk)
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ii) Give a reason for your answer in (b) (i) above. (1mk)
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c) Name the part labeled Y (1mk)
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Name the function of each of the following biological instruments (2mks)
a) Bait trap
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b) Pair of forceps
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The diagram below shows asexual reproduction in yeast cells.

a) Name the type of reproduction shown in the diagram (1mk)
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b) Identify the structure labeled A. (1mk)
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c) State the biological importance of A (1mk)
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Differentiate between
a) Genotype and phenotype of an organism. (2mks)
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b) Dominant gene and recessive gene. (2mks)
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a) What is nitrogen fixation? (1mk)
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b) In what form do plants take up nitrogen? (1mk)
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c) How is the nitrogen present in the tissues of an animal made available to plants.
(1mk)
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During oxidation of a certain food substance the respiratory quotient was found to be 0.718.
a) Name the type of food substance being oxidized. (1mk)
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b) State two advantages of using the food named above as a respiratory substance.

(2mks)
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Strips were cut lengthwise from the main stem of a herbaceous plant;
The diagram below shows the strips after placing them in different liquids

Account for the results obtained when the strips were put in
i) Distilled water (2mks)
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ii) In salt solution (2mks)
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How is spongy mesophyll adapted for the process of photosynthesis? (2mks)
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a) What is seed dormancy (1mk)
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b) State two importance of seed dormancy (2mks)
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Students in Bidii secondary school set up the apparatus shown below to demonstrate the breathing mechanism in a mammal.

What structure in a mammal is represented by each of the following
a) Glass tube (1mk)
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b) Balloons (1mk)
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c) Bell jar (1mk)
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d) Rubber sheet (1mk)
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a) State one function of golgi apparatus in a cell. (1mk)
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b) Name the organelle in the cell from which spindle fibres are formed. (1mk)
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Explain what happens in humans when concentration of glucose in the blood decreases below normal level. (4mks)
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The diagram below represents some stages in mitosis

a) Name the stages represented by the diagram labeled
M……………………………………………………………………………………(1mk)
N……………………………………………………………………………………..(1mk)
b) i) State the role of mitosis in growth and development of an organism. (1mk)
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ii) Name the region in a plant where mitosis actively takes place to bring about primary growth. (1mk)
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State two functions of the skin in a mammal (2mks)
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During a strenuous exercise the chemical process represented by the equation below takes place in the human muscle cells.

a) Name the process represented above (1mk)
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b) Name substance X (1mk)
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The equation below represents a process controlled by an enzyme N.

Process A……………………………………………………………………………..(1mk)
Enzyme N……………………………………………………………………………..(1mk)
b) Name a part in the human body where the above process takes place. (1mk)
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The diagram below represents a certain organism.

State the phylum and class to which it belongs (2mks)
Phylum……………………………………………………………….
Class …………………………………………………………………

What are the functions of the following in living organisms?
a) Phosphorus
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b) Calciferol (vitamin D) (2mks)
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a) State two functions of the spleen (2mks)
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b) In what form is carbon (IV) oxide transported in the blood? (2mks)
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Complete the table below

State the functions of the following parts of a light microscope.
a) Stage (1mk)
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b) Diaphragm (1mk)
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Below are two types of mammalian blood cells observed in a blood smear.

a) Give the identity of each cell
A…………………………………………………………………………………(1mk)
B…………………………………………………………………………………(1mk)
b) Which of the two cells would be more abundant in a blood smear? (1mk)
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Name a deficiency disease caused by lack of each of the following in man.
Iron…………………………………………………………………………………….(1mk)
Vitamin K……………………………………………………………………………...(1mk)

Why is it not suitable to use the transect and quadrat to estimate animal populations?
(1mk)

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State three structural differences between arteries and veins (3mks)
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