BIOLOGY SEMINAR ANSWERS 2026 - MERRYLAND HIGH SCHOOLS ENTEBBE,

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Item 1
Effects of human activities on the natural resources.
✓ deforestation as a result of clearing of large areas of land leading to global
warming hence increased temperatures. This leads to infertility of the area as its
always dry.
✓ loss of biodiversity due illegal poaching leading to reduced number of animal
species.
✓ illegal poaching leads to decline in wildlife population leading to extinction of animal
species.
✓ Poaching leads to loss of ecosystem balance as a result of disruption of the food
chains and food webs.
✓ Poaching leads to loss of tourism revenue as poached animals reduce the parks
appeal to visitors hence loss of jobs to the local people.
✓ Poaching leads to cultural heritage such as Uganda kobs when poached which
erodes traditional values and norms.
What can be done to reduce the effects
• deforestation solved by afforestation/agroforestry/re-afforestation
• setting up anti-poaching units by training more anti-poaching teams to protect
wildlife.
• Sensitization campaign on the community on importance to conserve the animals.
• Offering the community members employment in the ecotourism sector hence
becoming active partners in conservation.
Benefits of persevering heritage sites like UNESCO
• beautiful scenery to attract tourists leading to income and also provide
educational value to foreigners.
• Avoids extinction of animal and plants.
• Improved crop yield hence better harvest
• Preservation of the heritage provides cultural and historical value to the nation
• Job creation of those working there
©Biology Department Merryland High School
“Success is the sum of small efforts, repeated.” —R. Collier
Happiness
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Persistence and Perseverance
Item 2
Challenges of the factory on the river
✓ Water pollution by producing chemical wastes into the water that change the
water PH killing the living organisms such as fish hence reducing fish numbers.
✓ The factory releases hot water into the river after cooling the machines, this
changes the temperature of the water killing aquatic organisms.
✓ The river is enriched with chemicals such as nitrates and phosphates that favour
algal blooms which when decompose use up the oxygen leading to death of fish
species leading to reduced biodiversity.
✓ Air pollution as the factory releases toxic fumes into the atmosphere such as
Sulphur dioxide and nitrogen dioxide that dissolve in water causing acid rain that
burn plant leaves reducing on the photosynthetic rate of leaves of a plant. This
brings about reduced crop yield.
✓ Heaping of soil at the river bank leads to erosion of soil into the river leading to
chocking of the river with soil hence loss of habitat for fish.
✓ Noise pollution by the factory due to running machines that disturbs the
community’s peace and causes migration of people to new areas.
Ways to minimize the effects of the challenges
• Treating of wastes before release into the water body to overcome pollution.
• Afforestation/reforestation/agroforestry to absorb gases such as Carbondioxide
that bring about global warming and soil erosion.
• Construction of the factory away from the community to reduce on noise pollution.
• Fitting air filters in the chimneys of the vent pipes that take out the chemical
wastes into the air to reduce on air pollution.
• Cooling the water before release into the waterbody.
Value of conserving rivers
• River banks have soils that are used for growing vegetables as they give ready
water for irrigation.
• They are a source of clean water for animals to drink
• They contain sand that is a natural resource used for building bringing income.
Item 3
Environmental problems likely addressed by the town clerk and mayor
✓ Dumping of raw sewage leads to disease such as typhoid, cholera that affect
humans that use that water leading to poor health of the people.
©Biology Department Merryland High School
“Success is the sum of small efforts, repeated.” —R. Collier
Happiness
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Persistence and Perseverance
✓ Sewage contains nitrates and phosphates that enrich the water body favoring
nitrates and phosphates that favour algal blooms which when decompose use up
the oxygen leading to death of fish species leading to reduced biodiversity.
✓ Burning plastics and polythene releases toxic fumes into the air that cause
breathing difficulties to humans and their animals eventually leading to death.
✓ Clearing swamps for agriculture leads to habitat loss for organisms.
✓ When swamps are cleared, flooding of people’s homes occurs causing migrations
to occur.
✓ Depletion of sand which is a natural resource for building
✓ Many in cattle eat up vegetation and leave the land bear for agents of erosion to
carry away top soil hence reduce yields.
How to solve the above effects?
• Recycle and reuse plastics to clean up the environment
• Treatment of sewage before release into the water body to reduce on water
borne diseases
• Plant more trees/ agroforestry/Re-afforestation
• Sustainable use of swamps through reduced encroachment by sensitization.
• Paddock system of grazing to reduce on overcrowding of cattle.
c) why conserve swamps
➢ source of raw materials such as papyrus reeds for the local factory there by
supporting lively hoods.
➢ increases water purification before release into the main water body.
➢ swamps contain sand in them that is used for building
➢ mitigates floods as they absorb excess water and slowly release it into the
surrounding water bodies.
➢ Erosion control by shrubs, grasses tress
➢ Reduction in greenhouse gases as they absorb carbondioxide hence a happy planet
➢ They offer scientists research and education on biodiversity and economic
introduction.
Item 4
effects of environmental challenges
✓ clearing swamps for settlement leads to loss of habitat for living organism
such as fish leading to decreased yield for the fishing factory.
✓ clearing swamps reduces water purification hence causing water borne
diseases.
©Biology Department Merryland High School
“Success is the sum of small efforts, repeated.” —R. Collier
Happiness
Page 3 of 28
Persistence and Perseverance
✓ loss of raw materials for building industry such as papyrus
✓ extinction of endangered species of plants leading to their reduced numbers
as swamps are cleared.
✓ no space to settle during water flow as it runs off leading to flooding on
people’s houses hence their displacement due to clearing of swamps.
✓ deforestation as a results of clearing of large areas of land leading to global
warming hence increased temperatures. This leads to infertility of the area
as its always dry.
✓ loss of biodiversity due illegal poaching leading to reduced number of animal
species.
✓ increased soil erosion that leads to loss of top soil for crop growth hence
reduced crop yield as a result of deforestation.
✓ Water pollution by producing chemical wastes from the factory water that
changes the water PH killing the living organisms such as fish hence reducing
fish numbers.
✓ The various factories release hot water into the wetland after cooling the
machines, this changes the temperature of the water killing aquatic organisms.
✓ The wetland is enriched with chemicals such as nitrates and phosphates from
the factories that favour algal blooms which when decompose use up the
oxygen leading to death of fish species leading to reduced biodiversity.
✓ Air pollution as the factories releases toxic fumes into the atmosphere such
as Sulphur dioxide and nitrogen dioxide that dissolve in water causing acid rain
that burn plant leaves reducing on the photosynthetic rate of leaves of a plant.
This brings about reduced crop yield.
How to overcome the above environmental challenges
✓ strengthening legal laws by limiting encroachment of wetlands
✓ promote sustainable agricultural practices such as agroforestry in the wetland to
benefit from food security.
✓ rehabilitation of the damaged wetland by planting native vegetation, restoring
water channels
✓ promote public awareness education by involving community in decision making
regarding wetlands.
✓ Alternative livelihoods for the local communities such as ecotourism to learn more
about conservation in other areas.
Importance of NEMA restoring the wetland to original state
➢ source of raw materials such as papyrus reeds from swamps for the local factory
there by supporting lively hoods.
➢ increases water purification before release into the main water body.
©Biology Department Merryland High School
“Success is the sum of small efforts, repeated.” —R. Collier
Happiness
Page 4 of 28
Persistence and Perseverance
➢ Support biodiversity and ecosystems
➢ mitigates floods as they absorb excess water and slowly release it into the
surrounding water bodies.
➢ Erosion control by shrubs, grasses tress
➢ Reduction in greenhouse gases as they absorb Carbondioxide hence a happy
planet.
ELEMENT OF CONSTRUCT 2
Item 5
a.
• There was closed spacing, growing of the plants very close to each other which
caused stiff competition for growth factors like nutrients, light, air required by
the plant to grow and carryout photosynthesis.
• There was also a wrong pattern of planting; when the maize plants were planted
earlier which led to rapid exhaustion of nutrients in the soil such as Nitrogen,
ammonium ions required for proper growth of the plants.
• The garden being close to a dusty road caused the dust to accumulate on the
leaves of the plants which reduced on the rate of absorption of light energy by
the chlorophyl of the leaves which reduced on the rate of formation of starch by
the plants.
• Late planting of the beans caused the beans to be shaded and covered by the
already tall long maize plants which reduced the photosynthetic rate of beans of
the beans thus stunted growth
b.
• Beans should be planted earlier in the garden or together with the maize since
they are leguminous plants with root nodules with nitrogen fixing bacteria that
fix nitrogen to form nitrate ions need by the plant for proper growth.
• Thinning out of some plants especially maize to create more space and light
penetration to all plants for efficient photosynthesis to improve yields.
• Trees can be planted alongside the roads to trap some dust from the dusty road
in the future and reduce on soil erosion.
• Irrigation to remove dust on leaves and moisture needed for proper germination
of seeds.
Item 6
a). i)
Nancy's garden was next to a dusty road leading to accumulation of dust onto the leaves,
covering the surface and stomata reducing the surface area for trapping sunlight and
absorption of Carbondioxide respectively, hence reducing the rate of photosynthesis.
©Biology Department Merryland High School
“Success is the sum of small efforts, repeated.” —R. Collier
Happiness
Page 5 of 28
Persistence and Perseverance
ii).
Bees, acted as pollinators and carried pollen grains from the anther heads to the stigma
of bean flowers. When the pollen grains landed on mature stigma, they germinated and
produced pollen tubes which grew via the micropyle to the embryo sac. Its generative
nucleus divided by mitosis to form two male nuclei. One male nucleus fused with the egg
cell to form the seed embryo comprising the plumule and radicle. The second male nucleus
fused with the polar nucleus to form the seed primary endosperm. The ovary wall formed
the fruit wall and the integuments formed the seed coat.
b).
They developed root nodules where the nitrogen-fixing bacteria converted nitrogen to
form nitrates, Nitrites used by the plants to grow.
Possessed broad leaves which trapped sunlight for photosynthesis .
They formed deeper roots to increase surface area for water absorption and anchorage.
Production of more root hairs to increase surface area for water absorption.