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Biology
Paper 1
(Theory)
Friday 30th May, 2025
BUKOYO SECONDARY SCHOOL
Uganda Certificate of Education
S.4 BEGINNING OF TERM 2 EXAMS 2025
BIOLOGY
Paper 1
(Theory)
2 hours 30 minutes
INSTRUCTIONS TO CANDIDATES
This paper consists of two sections; A and B
It has five examination items. Section A has three compulsory items
Section B has two parts; I and II. Answer one item from each part.
Answers to section A must be written in the spaces provided while answers to section B
must be written in the answer sheets provided.
Answer five items in all.
FOR EXAMINER’S USE ONLY
ITEM 1 2 3 4 5 TOTAL
SCORES
Page 1 of 7
SECTION A (all items are compulsory in this section)
Item 1
Mr. Paskari is a prominent farmer in Gulu district. Recently he hired a new land for crop
farming. Later he planted the seeds, few seedlings managed to grow and these later produced
crops which were small, with few small flowers and yellow leaves which later gave low fruit
yields. Later when he brought a specialist to analyze the cause of the low yields, the specialist
reported that the soils were deficient in some essential mineral ions.
Task
a) Identify the plant processes that were affected
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b) Explain how the affected plant processes led to low yields.
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Page 2 of 7
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c) Why was Mr. Paskari able to get some yields?
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Item 2
Sarah is a p.7 pupil who is very bright in class. However, when she sits on the front row near the
chalk board, she cannot see the writings on the chalk board, and she complains of pain in her
eyes when she strains them to see in the work in her books. One day as she was coming from
school, she closed her eye very fast and unconsciously as a speeding insect entered her eye. She
later wondered how such a response happened to protect her eyes.
Task
a) Describe a series of events that occurred in Sarah’s body to bring about the response that
protected her eyes.
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Page 3 of 7
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b) Using scientific facts, explain Sarah’s problem and its cause to her parents.
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c) Using illustrations, clearly show how Sarah’s problem can be managed.
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Item 3
Kizito a 16 year old boy at Nakaloke recently got involved in a sexual affair with Maria; a 15
year old girl. From their affair, Maria conceived and they expect a baby. Kizito’s parents denied
their son’s responsibility for this pregnancy. They claimed that the boy was still too young to
make a girl pregnant. Maria was advised by her peers to terminate the pregnancy on grounds
that the child would be father less.
Page 4 of 7
Task
a) Explain to Kizito’s parents that it is very possible for their son to make Joyce pregnant and
describe the process by which Maria got pregnant.
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b) Explain the problems Maria is likely to face if she takes the advice given by her parents.
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c) Advice other adolescents on how to avoid the challenges faced by Kizito and Maria
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Page 5 of 7
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SECTION B (attempt any one item from each part)
Part 1
Item 4
In the recent times, there has been a cry of climate change, which is believed to be caused
mainly by increased levels of greenhouse gases. The increased levels of fossil fuel burning,
industrialization and agriculture is the main cause of the increase in the concentration of
greenhouse gases. The table below shows how the concentrations of three gases have increased
between 1890 and 1990 and their expected concentrations in 2030.
gas Concentration of gas in the atmosphere in a certain year (parts
per million)
1890 1990 2030
Carbon dioxide 290 354 400-500
Methane 0.9 1.7 2.2-2.5
Nitrous oxide 0.28 0.3 0.33-0.35
Task
a) Explain the environmental challenges the above changes in greenhouse gases have caused
b) How is it important to nature to maintain the levels of the above gases at environmentally
friendly levels
c) Provide practical remedies to lower the concentration of the above gases
Page 6 of 7
Part II
Peter and john who are blood group A and B respectively got a fatal accident and lost a lot of
blood. When they were taken to the health center IV, the doctor used their blood to test the blood
group of individuals X, Y and Z so as to find a suitable donor. Later examinations revealed that
john had severely injured his pancreas.
The table below shows the result.
person X Y Z
Peter Clumps Clumps No clumping
John No clumping Clumps No clumping
Task
a) Identify the blood groups of individuals X, Y and Z
b) Explain how the accident affected john’s body functioning.
c) Without referring Peter and John to another hospital, suggest with reasons which
individuals could donate blood to peter and John
END
GOODLUCK
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