Biology Past Questions and Answers 2025

 

PAPER 2 [THEORY]

Essay

[70 marks]

1 hour 40 minutes

Answer three questions in all: two questions from Section A and the compulsory question in Section B.

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Section A

[40 marks]

Answer two Questions only from this section

Question 1

Two Spirogyra filaments A and B were each placed in concentrated sugar solution and dilute sugar solution, in different beakers respectively. The setups were left for one hour.

(a) Which of the filaments was placed in a:
(i) hypotonic solution; _____________________ [2 marks]
(ii) hypertonic solution? ___________________ [2 marks]

(b) If the cells of the filaments were observed under a microscope, state two changes each that would be observed in the cells of filament:
(i) A: ________________________________________

(ii) B: ________________________________________
________________________________________ [4 marks]

(c) Name the process that led to the changes in the cells of filament:

(i) A: ________________________________________
(ii) B: ________________________________________ [2 marks]

(d) (i) What is homeostasis? ________________________ [2 marks]
(ii) State one function of the mammalian skin in homeostasis. [1 mark]

(e) Make a diagram 8 cm to 10 cm long of the longitudinal section of a mammalian skin and label only the parts that perform the following functions:
(i) production of sebum;
(ii) production of sweat;
(iii) makes the hair shaft stand erect;
(iv) transmits the stimulus of touch.            [9 marks]

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Question 2

(a) (i) What are microelements in plant nutrition? ___________________________ [2 marks]
(ii) Give three examples of microelements. __________________________________ [3 marks]

(b) Complete the table below:

Element	One importance of element in plants	One deficiency symptom of element in plants
Nitrogen	Protein synthesis
Magnesium
Phosphorus
Potassium		Yellowing of leaves

                                                                                                                                                     [6 marks]

(c) Name the phases of photosynthesis. _________________________________ _________________________________         [2 marks]

(d) Complete the table below:

Organ	Fluid produced	Where fluid is stored	Two functions of fluid in digestion	Site of action for fluid produced
		Gall bladder

                                                                                                                                                [5 marks]

(e) On the table below, state two differences between the alimentary canal of a domestic fowl and the alimentary canal of a human.

Alimentary canal of a domestic fowl	Alimentary canal of a human

                                                                                                                                [2 marks]

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Question 3

(a) Explain briefly the term ecosystem. ________________________________ [3 marks]

(b) State four ways by which plants are beneficial to animals. _______________ [4 marks]

(c) Explain briefly how the following ecological components affect the population of Talinum in a garden:
(i) temperature: ___________________________
(ii) herbivores: ___________________________
(iii) rainfall: _____________________________
(iv) decomposers: _________________________ [4 marks]

(d) Explain briefly each of the following biological associations:
(i) commensalism: ________________________________________
(ii) mutualism: ___________________________________________ [8 marks]

(e) Name one method of enumerating the population size of mango trees in a community. ____________________ [1 mark]

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Question 4

A cross between two parents, each heterozygous (Aa) for albino trait, produced four offspring. Use the information to answer questions 4(a) to 4(c).

(a) Using a genetic diagram, show the possible genotypes of the offspring. [8 marks]

(b) Give the:
(i) phenotype of the parents; __________________________ [1 mark]
(ii) genotypic ratios of the offspring; ___________________ [2 marks]
(iii) number of offspring that will not be albino; _________ [1 mark]
(iv) number of offspring that will be albino; _____________ [1 mark]
(v) reason for the answer in 4(b)(iv). __________________ [1 mark]

(c) (i) State the type of cross in 4(a). __________________ [1 mark]
(ii) Mention the law of genetics that supports the genotypes of the offspring in 4(a). __________________ [1 mark]

(d) In a genetics class, the following answers were obtained from different genetic crosses. Place them under their appropriate genetic terms.

(i) All white fur.
(ii) BB, BB, Bb, Bb.
(iii) 3 wrinkled seeds and 1 smooth seed.
(iv) AS, AS, AS, AS.

Genotype	Phenotype

                                                                                                                               [4 marks]

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Section B (30 marks)

Answer all Question in this section

Question 5

(a) (i) Name two processes by which leaves of plants lose water. __________ [2 marks]
(ii) Explain briefly each of the processes named in 5(a)(i). _________________ [4 marks]

(b) (i) Arrange the following structures of a stem, from the inner part to the outer part.

• Medullary ray
• Cortex
• Epidermis
• Pith

(ii) Name three forces that move water from the roots to the leaves of plants. [3 marks]

(c) Explain briefly how Spirogyra survives in a dry pond. ______________ [4 marks]

(d) (i) Explain briefly the term Recombinant DNA technology. _________ [4 marks]
(ii) State two applications of Recombinant DNA technology. ___________ [3 marks]

(e) Distinguish between:
(i) bilateral symmetry and radial symmetry; ______________ [2 marks]
(ii) longitudinal section and transverse section. ___________ [2 marks]

(f) (i) What is antenatal care? _______________________ [2 marks]
(ii) List two benefits derived from antenatal visits. _________ [2 marks]

WASSCE Biology 2025 Solutions

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Question 1

Two Spirogyra filaments A and B were each placed in concentrated sugar solution and dilute sugar solution, in different beakers respectively.

(a)
(i) Filament A in dilute sugar solution → hypotonic solution
(ii) Filament B in concentrated sugar solution → hypertonic solution

(b)
(i) Filament A (hypotonic):

• Cells become turgid.

• Cytoplasm presses against cell wall.

(ii) Filament B (hypertonic):

• Cells undergo plasmolysis.

• Cytoplasm shrinks away from cell wall.

(c)
(i) A → Osmosis (endosmosis)
(ii) B → Osmosis (exosmosis)

(d)

(i) Homeostasis → process by which organisms maintain a constant internal environment despite external changes.
(ii) Function of skin → regulates body temperature via sweating/vasodilation.

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(e) Diagram of mammalian skin:

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Question 2

(a)
(i) Microelements → mineral elements needed in very small/trace amounts for plant growth.
(ii) Examples → Iron (Fe), Manganese (Mn), Copper (Cu), Zinc (Zn), Boron (B), Molybdenum (Mo). (Any 3)

(b) Complete table:

Element	Importance in plants	Deficiency symptom
Nitrogen	Protein & chlorophyll synthesis	Stunted growth, yellowing of older leaves
Magnesium	Central atom of chlorophyll; activates enzymes	Yellowing between veins (interveinal chlorosis)
Phosphorus	Formation of ATP, nucleic acids, energy transfer	Poor root growth, stunted growth
Potassium	Enzyme activation, stomatal regulation, protein synthesis	Yellowing/burning of leaf margins

(c) Phases of photosynthesis →

1. Light-dependent (photochemical/light reaction)
2. Light-independent (dark reaction/Calvin cycle)

(d)

Organ	Fluid produced	Where fluid is stored	Two functions	Site of action
Liver	Bile	Gall bladder	(i) Emulsifies fats	Duodenum
			(ii) Neutralizes stomach acid

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(e) Differences:

Domestic fowl	Human
Has crop & gizzard	No crop, no gizzard
No teeth, uses gizzard to grind food	Teeth present for chewing
Short alimentary canal (herbivory adapted)	Longer canal

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Question 3

(a) Ecosystem → a natural unit comprising living organisms (biotic community) interacting with non-living environment (abiotic factors).

(b) Benefits of plants to animals:

1. Provide oxygen through photosynthesis.
2. Provide food (carbohydrates, proteins, fruits).
3. Provide shelter and protection.
4. Source of medicine.
5. Prevent erosion and maintain soil fertility.      (Any 4)

(c) Effects on Talinum:

• Temperature: affects enzyme activity and growth rate.
• Herbivores: reduce population by grazing.
• Rainfall: increases soil moisture and growth.
• Decomposers: enrich soil nutrients for growth.

(d)
(i) Commensalism → association where one benefits while the other is neither harmed nor benefited. Example: Epiphytes on trees.
(ii) Mutualism → both species benefit. Example: Nitrogen-fixing bacteria and legumes.

(e) Method → Quadrat sampling or Census method (for trees).

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Question 4

(a) Genetic diagram:

Parents: Aa × Aa

Gametes: A, a × A, a

Punnett square:

	A	a
A	AA	Aa
a	Aa	aa

Offspring → AA : Aa : Aa : aa

(b)
(i) Phenotype of parents → Normal (non-albino)
(ii) Genotypic ratio → 1AA : 2Aa : 1aa
(iii) Non-albino offspring → 3 (AA + 2Aa)
(iv) Albino offspring → 1 (aa)
(v) Reason → aa lacks melanin (homozygous recessive).

(c)
(i) Type of cross → Monohybrid cross
(ii) Law → Mendel’s Law of Segregation

(d) In a genetics class, the following answers were obtained from different genetic crosses. Place them under their appropriate genetic terms.

(i) All white fur.
(ii) BB, BB, Bb, Bb.
(iii) 3 wrinkled seeds and 1 smooth seed.
(iv) AS, AS, AS, AS.

Genotype	Phenotype
(ii) BB, BB, Bb, Bb	(i) All white fur
(iv) AS, AS, AS, AS	(iii) 3 wrinkled seeds and 1 smooth seed

✅Explanation

• Genotype refers to the genetic makeup (letters, e.g., BB, Bb, AS).
• Phenotype refers to the observable characteristics (e.g., white fur, wrinkled seeds).

So:

• (ii) is a list of genotypes → BB, BB, Bb, Bb.
• (iv) is also a genotype set → AS, AS, AS, AS.
• (i) describes a phenotype (all offspring appear white).
• (iii) describes a phenotypic ratio (3 wrinkled : 1 smooth).

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Question 5

(a)
(i) Processes of water loss in leaves:

• Transpiration
• Guttation

(ii) Explanation:

• Transpiration → evaporation of water from stomata/cuticle.
• Guttation → loss of water droplets from hydathodes.

(b)
(i) Arrangement (inner → outer):
Pith → Medullary ray → Cortex → Epidermis

(ii) Forces moving water:

• Root pressure
• Capillarity (adhesion/cohesion)
• Transpiration pull

(c) Spirogyra in dry pond → forms zoo-spores/akinetes or develops protective mucilage cysts to resist desiccation until water returns.

(d)
(i) Recombinant DNA technology → artificial combining of DNA from two different sources to form new genetic combinations.
(ii) Applications:

• Production of insulin, vaccines.
• Genetically modified crops (pest/drought resistance).

(e)
(i) Bilateral vs radial symmetry:

• Bilateral: body divisible into two equal halves along one plane (e.g. humans).
• Radial: body divisible along many planes (e.g. hydra, starfish).

(ii) Longitudinal vs transverse:

• Longitudinal section → cut along the length.
• Transverse section → cut across the width.

(f)
(i) Antenatal care → medical care given to a pregnant woman before delivery.
(ii) Benefits:

• Monitors growth and health of baby.
• Early detection of complications.
• Provides health education to mother.

choice 

📥 Download Biology Past Questions 2025 PDF

✅ WASSCE BIOLOGY 2025 (Objectives)

Answer all the questions.

Each question is followed by four options lettered A to D. Find the correct option for each question and shade in pencil on your answer sheet, the answer space which bears the same letter as the option you have chosen. Give only one answer to each question. An example is given below.

Which part of the gill of fish is involved in gaseous exchange? Gill
A. slits
B. bars
C. covers
D. filaments

The correct answer is filaments, which is lettered D and therefore answer space D would be shaded.

[ A ] [ B ] [ C ] ■

Think carefully before you shade the answer spaces; erase completely any answer(s) you wish to change.

Do all rough work on this question paper.

Now answer the following questions.

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1. A measure that aids conservation of trees is

A. inadequate funding of forestry projects.
B. killing of all herbivores.
C. inadequate number of forest guards.
D. regular planting of tree crops.

2. The resources that will mostly be conserved are
A. mineral resources and forests.
B. soil and water.
C. wildlife and forest.
D. soil and forest.

3. Which of the following statements is not an advantage of the game reserve to the host community?
A. Preservation of species
B. Tourism
C. Income
D. Food for predators

4. The practice that cannot be used when conserving nonrenewable resources is the use of
A. ethanol to power cars and generating sets.
B. electric cars.
C. solar panels to light up homes.
D. petrol and diesel engines in cars.

5. Which of the following statements about variation in humans is not correct?
A. Variations can be observed in behaviours or physical appearance.
B. Human populations have same features but each differs from others
C. All kinds of variations in a population will be inherited
D. Blood group is an example of variation

6. Which of the following genotypic ratios would be obtained when two heterozygous white pea plants are crossed?
A. 1:2
B. 1:1
C. 3:1
D. 1:2:1

7. What determines the sex of a baby? The
A. father’s X and Y chromosomes
B. father’s X and X chromosomes
C. mother’s X and X chromosomes
D. mother’s X and Y chromosomes

8. A worker honeybee communicates with others about the location of a source of food through
A. stinging.
B. tactile touching.
C. dancing.
D. chemical signal.

9. The body parts show an evidence of evolution from
A. systematics.
B. fossil records.
C. embryology.
D. vestigial organs.

10. The explanation for the use of the body parts as an evidence of evolution is that they
A. have never been useful to closely related organisms.
B. were once useful to ancestral species.
C. are useful body parts in humans.
D. are larger in humans than in the organisms where they are useful.

11. Which of the following statements about a food web is not correct?
A. It contains two or more food chains
B. It involves more organisms
C. It involves complex feeding relationships
D. Organisms in a food web have less chances of survival

12. Which of the following associations is an example of parasitism?
A. Bacteria in the rumen of ruminants
B. Alga and fungus
C. Mistletoe and flowering plants
D. Lion and goat

13. People living in an industrial area where heavy machineries are used always raise their voices when talking to one another. What is likely responsible for the behaviour?
A. They lack communication etiquette
B. They are excited
C. They have partial deafness due to noise pollution
D. It is their usual habit

14. The use of predatory fish to control the population of mosquito larvae is a form of
A. chemical control.
B. physical control.
C. biological control.
D. mechanical control.

15. Which of the following organisms is the vector of river blindness?
A. Blackfly
B. Tsetse fly
C. Mosquito
D. Moth

16. The first stage in the scientific method of investigation is
A. assembling materials and equipment.
B. stating the hypothesis.
C. observation to identify the problem.
D. setting up the control experiment.

17. The diagram is an illustration of a
A. dicotyledonous root.
B. dicotyledonous stem.
C. monocotyledonous stem.
D. monocotyledonous root.

18. The parts labelled I and II respectively are
A. cortex and phloem.
B. bark and xylem.
C. cortex and xylem.
D. pith and phloem.

19. The feature common to the group of plants is that they
A. have broad leaves.
B. do not have flowers.
C. bear enclosed seeds.
D. lack true roots, stem and leaves.

20. The plants belong to Division
A. Coniferophyta.
B. Angiospermophyta.
C. Bryophyta.
D. Chlorophyta.

21. Which of the following blood group genotypes cannot be for the daughter?
A. IᴬIᴼ
B. IᴮIᴼ
C. IᴬIᴬ
D. IᴬIᴮ

22. If both parents are homozygous, the blood group of the son and the daughter would be
A. IᴬIᴮ.
B. IᴬIᴬ.
C. IᴬIᴼ.
D. IᴮIᴼ.

23. A test cross is used to determine an unknown genotype of an organism by crossing the organism with another organism of
A. unknown genotype.
B. known homozygous recessive genotype.
C. known heterozygous genotype.
D. known homozygous dominant genotype.

24. The reason why a sickle cell carrier is discouraged from getting married to another sickle cell carrier is because they are likely to have children that are
A. AA.
B. carriers of sickle cell.
C. SS.
D. haemophiliac.

25. If the strand sequence of bases for a DNA molecule is CTT, AGA, CTA and ATA, its corresponding RNA sequence would be
A. CUU, AGA, CUA, AUA.
B. GAA, TCT, GAT, TAT.
C. GAA, UCU, GAU, UAU.
D. GUU, ACA, GUA, AUA.

26. The parts of the seedling that showed the effect of geotropism are
A. cotyledon and plumule.
B. cotyledon and radicle.
C. plumule and radicle.
D. plumule and testa.

27. The part of the seedling that responded positively to geotropism is
A. radicle.
B. plumule.
C. cotyledon.
D. testa.

28. The structure in the seedling that would develop into the shoot is the
A. radicle.
B. plumule.
C. cotyledon.
D. testa.

29. Which of the labelled parts is the lag phase?
A. I
B. II
C. III
D. IV

30. At which phase is the growth rate greater than the death rate?
A. I
B. II
C. III
D. IV

31. The products of photosynthesis in plants are
A. water and carbon (IV) oxide.
B. glucose and oxygen.
C. glucose and water.
D. chlorophyll and oxygen.

32. Which of the following vitamins is important in blood clotting?
A. Vitamin D
B. Vitamin B
C. Vitamin E
D. Vitamin K

33. The deficiency disease that results from the lack of vitamin B in humans is
A. rickets.
B. scurvy.
C. beriberi.
D. kwashiorkor.

34. The food substance likely present in the filtrate in test tube A is
A. milk protein.
B. reducing sugar.
C. oil.
D. cooked starch.

35. The blue-black colour observed in test tube B is an indication that
A. the mixture was heated.
B. the control experiment is wrong.
C. the result of the experiment is positive.
D. too much of iodine solution was used.

36. Which of the labelled parts is a vestigial structure?
A. I
B. II
C. III
D. IV

37. What type of joint is formed at the part labelled IV?
A. Gliding and suture
B. Hinge
C. Pivot
D. Ball and socket

38. Which of the following vessels of the heart contains the most oxygenated blood?
A. Posterior vena cava
B. Pulmonary vein
C. Anterior vena cava
D. Pulmonary artery

39. Which of the following respiratory structures are possessed by terrestrial animals?
A. Gills
B. Breathing roots
C. Stomata
D. Lungs

40. The substance that produces the oxygen that is given off during photosynthesis is
A. air.
B. water.
C. carbon (II) oxide.
D. sunlight.

41. Ecologists work in the following areas except
A. oceans.
B. forests.
C. food industries.
D. hot deserts.

42. The major habitat of homeotherms is
A. marine.
B. freshwater.
C. terrestrial.
D. estuarine.

43. Which of the following ecological factors is unique to brackish water?
A. Dissolved oxygen
B. Low light intensity
C. Moderate salinity
D. High temperature

44. Which of the following instruments is used to measure water transparency?
A. Anemometer
B. Secchi disc
C. Hydrometer
D. Photometer

45. Lichens are living organisms composed of
A. sea anemone and hermit crab.
B. algae and sea anemone.
C. termite and protozoa.
D. algae and fungi.

46. Which of the following terms describes the ability of the body to maintain a steady internal environment?
A. Catabolism
B. Tolerance
C. Homeostasis
D. Metabolism

47. Which of the following pathways shows how a nerve impulse is transmitted?
A. Dendrites → cell body → axon → synapse
B. Axon → cell body → synapse → dendrites
C. Synapse → cell body → dendrites → axon
D. Axon → dendrites → synapse → cell body

48. The part of the human eye that prevents internal reflection of light is the
A. choroid.
B. cornea.
C. iris.
D. vitreous humour.

49. After fertilisation in flowers, the ovary develops to form the
A. fruit.
B. seed.
C. cotyledon.
D. endosperm.

50. A faster colour change of a dry cobalt chloride paper affixed to the lower surface of a leaf compared to that at the upper surface indicates that
A. the lower surface of a leaf has more stomata than the upper surface.
B. sunlight slows down water loss from the lower surface.
C. sunlight causes the stomata at the upper surface to close.
D. stomata are not present at the upper surface of the leaf.

END OF PAPER

✅ WASSCE Biology 2025 Objective Answers (1–50)

Question	Answer	Explanation (brief)
1	D	Planting trees conserves forests.
2	C	Wildlife & forests are conserved in game reserves.
3	D	Predators feeding in reserves is not an advantage to host.
4	D	Petrol/diesel are non-renewable, not conservation.
5	C	Not all variations are inherited; some are environmental.
6	D	Heterozygote × heterozygote → 1:2:1 ratio.
7	A	Father’s X or Y chromosome determines sex.
8	C	Honeybees dance to communicate food source.
9	D	Vestigial organs show evolutionary evidence.
10	B	Vestigial organs were once useful in ancestors.
11	D	Food webs increase survival chances, not reduce.
12	C	Mistletoe (parasite) + flowering plant (host).
13	C	Noise pollution causes partial deafness.
14	C	Predatory fish = biological control.
15	A	Blackfly transmits Onchocerca → river blindness.
16	C	First stage of science → observation.
17	B	Diagram is a dicot stem (with vascular bundles in a ring).
18	C	I = Cortex, II = Xylem.
19	B	Bryophytes lack flowers.
20	C	Mosses/liverworts → Division Bryophyta.
21	D	Daughter cannot be AB with A and B parents (genetics).
22	A	Homozygous A × B → children = AB.
23	B	Test cross = unknown × homozygous recessive.
24	C	Carrier (AS) × carrier (AS) may produce SS.
25	A	DNA: CTT, AGA, CTA, ATA → RNA: CUU, AGA, CUA, AUA.
26	C	Geotropism seen in radicle (+) and plumule (–).
27	A	Radicle grows downward (+ve geotropism).
28	B	Plumule develops into shoot.
29	A	Phase I = lag phase (no growth).
30	C	Phase III = log/exponential growth → growth > death.
31	B	Photosynthesis products: glucose + oxygen.
32	D	Vitamin K aids blood clotting.
33	C	Vitamin B deficiency → beriberi.
34	B	Filtrate contains reducing sugars (Benedict’s test).
35	C	Blue-black = positive test for starch.
36	C	III (coccyx) = vestigial bone.
37	D	Hip joint (pelvis-femur) = ball and socket.
38	B	Pulmonary vein carries oxygenated blood from lungs.
39	D	Terrestrial animals use lungs.
40	B	Oxygen in photosynthesis comes from water photolysis.
41	C	Ecologists do not work in food industries.
42	C	Homeotherms mainly live on land (terrestrial).
43	C	Brackish water unique factor = moderate salinity.
44	B	Secchi disc measures water transparency.
45	D	Lichen = fungus + alga.
46	C	Homeostasis = steady internal environment.
47	A	Pathway: dendrite → cell body → axon → synapse.
48	A	Choroid prevents internal reflection.
49	A	Ovary develops into fruit.
50	A	More stomata on lower surface → faster cobalt paper colour change.

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