Form Four Biology NECTA review papers by year
The 2025 paper is free here. 2010 to 2024 are on the app
Past national papers show you how NECTA sets questions. Sit a paper under exam conditions, then use the suggested answers to find the topics you still need to revise.
Looking for an earlier year? The NECTA Form Four Biology papers from 2010 to 2024 are in the Click Online Academy app on Google Play.
2025 NECTA Form Four Biology paper (CSEE 033/1 Biology 1)
National Examinations Council of Tanzania · Time: 3 hours · Section A: 16 marks · Section B: 54 marks · Section C: 30 marks
Instructions from the paper:
• This paper has sections A, B and C, with eleven (11) questions in total.
• Answer all questions in Sections A and B, and two (2) questions from Section C.
• Section A carries 16 marks, Section B 54 marks and Section C 30 marks.
• Write in blue or black pen, except for drawings, which must be in pencil.
How to use this page: choose an option for each multiple-choice question and click “Check Answer”. A correct answer plays a short sound and shows an explanation; a wrong answer shows the right option and why. For the matching item and written questions, answer on paper first, then click “View Answer”.
About the answers: they were prepared by Click Online Academy for revision. They are not the official NECTA marking scheme. If you are unsure about an answer, check with your Biology teacher.
SECTION A (16 marks): Question 1, Multiple Choice (10 marks)
1. For each of the items (i) to (x), choose the correct answer from among the given alternatives.
(i) Farmers at Mtakuja village observed a continuous decrease in the amount of beans yield in their farms. What is this step in the scientific process referred to?
(ii) Form Two students who recently visited Mikumi National Park saw zebra, shrubs, giraffe, lion, cheetah, grasses and mushroom. Which of these organisms would they group as primary consumers?
(iii) To make doughnuts, a woman mixed wheat flour, yeast, sugar and water, kneaded the mixture and covered it. After half an hour the dough rose. Which ingredient made the dough rise?
(iv) A bleeding pregnant woman was confirmed to have an embryo implanted in the fallopian tube. Which complication was she suffering from?
(v) Which mechanism does the human body undergo in response to cold weather?
(vi) Which diseases occur worldwide?
(vii) You notice that water has spilled on the floor of the classroom. What would you do to prevent an accident?
(viii) Which one of the following is NOT a part of a movable joint?
(ix) Which of the following are examples of sex-linked characteristics in humans?
(x) Organisms in class Reptilia have dry skin with horny scales. Which of the following organisms belong to this class?
SECTION A: Question 2, Matching Items (6 marks)
2. Match the roles of the hormones in List A with their corresponding hormones in List B. Write the letter of the correct response beside the item number.
| # | List A | Your answer |
|---|---|---|
| (i) | Controls contraction and relaxation of the uterine walls during birth. | |
| (ii) | Promotes conversion of excess glucose into glycogen in the blood. | |
| (iii) | Regulates the amount of water reabsorbed in the kidney tubules. | |
| (iv) | Stimulates milk production in lactating mammals. | |
| (v) | Controls metabolic activities in the body. | |
| (vi) | Promotes development of secondary sexual characteristics in females. |
List B
- A. Antidiuretic
- B. Thyroxine
- C. Adrenaline
- D. Oxytocin
- E. Glucagon
- F. Insulin
- G. Oestrogen
- H. Prolactin
Suggested answer
- (i) D: Oxytocin
- (ii) F: Insulin
- (iii) A: Antidiuretic hormone
- (iv) H: Prolactin
- (v) B: Thyroxine
- (vi) G: Oestrogen
SECTION B (54 marks): Questions 3 to 8
3. Mkutano villagers use traditional methods to process, preserve and store a variety of foods they obtain from their daily activities. Outline six advantages of such methods.
Suggested answer and marking guide
Advantages, any six
- Low cost: They use cheap, locally available materials, so most families can afford them.
- Simple: They need little training or special equipment.
- No electricity needed: Methods such as sun drying, smoking and salting work where there is no power supply.
- Fewer chemicals: Foods are not treated with artificial preservatives, so they are safer to eat.
- Less food wastage: Surplus food is kept instead of rotting, which reduces spoilage.
- Food available all year: Stored food can be eaten in dry seasons or times of scarcity.
- Extra income: Processed foods can be sold, and the products often keep a good taste and flavour.
- Environmentally friendly: Most methods produce little pollution.
4. With the aid of a labelled diagram, describe the events which take place during the prophase stage of mitosis.
Suggested answer and marking guide
Labelled diagram: animal cell in prophase
In the exam, draw in pencil, give the diagram a title and label with straight lines.
Events during prophase
- The chromatin threads coil and shorten, so the chromosomes become visible
- Each chromosome is made of two identical sister chromatids joined at the centromere
- The nucleolus disappears
- The nuclear membrane breaks down, so the chromosomes lie free in the cytoplasm
- In animal cells, the centrioles move to opposite poles of the cell
- Spindle fibres begin to form between the poles
5. How are the cardiac muscles adapted to perform their roles? Give six points.
Suggested answer and marking guide
Adaptations, any six
- Myogenic contraction: The muscle can contract and relax by itself without a nerve impulse, so the heart beats continuously.
- Branched, interconnected fibres: Impulses spread quickly, so the muscle contracts in a coordinated way.
- Intercalated discs: These junctions between cells let impulses pass quickly from cell to cell.
- Many mitochondria: They supply a constant, large amount of energy (ATP) for continuous work.
- Rich blood supply: Coronary vessels bring plenty of oxygen and nutrients and remove wastes.
- Resistance to fatigue: The muscle can work non-stop through life without tiring.
- Thick muscular walls in the ventricles: They produce enough force to pump blood to the lungs and the whole body.
- Striated fibres with a single central nucleus: This gives strong, regular contractions.
6. Bacteria, Amoeba and non-flowering plants reproduce asexually. Explain three merits and three demerits of the type of reproduction exhibited by these organisms.
Suggested answer and marking guide
Merits, any three
- Rapid reproduction: Many offspring are produced in a short time.
- Only one parent needed: The organism does not need to find a mate, which saves time and energy.
- Good traits are kept: Offspring are genetically identical to the parent, so successful features are passed on.
- Quick colonisation: The organisms can spread quickly into a favourable habitat.
Demerits, any three
- No genetic variation: All offspring are alike, so there are few new features to help adaptation.
- Vulnerable population: A disease or environmental change can wipe out all the individuals.
- Overcrowding: Many offspring close together compete for food, space and light.
- Harmful traits are passed on: Any weakness in the parent is inherited by every offspring.
7. A man with heterozygous blood group A married a woman with heterozygous blood group B. One of their offspring had blood group O. Use a genetic cross to show the probability of producing such an offspring.
Suggested answer and marking guide
Heterozygous group A is IAi and heterozygous group B is IBi.
- Parental phenotypes: blood group A × blood group B
- Parental genotypes: IAi × IBi
- Gametes: IA or i, and IB or i
| IB | i | |
|---|---|---|
| IA | IAIB group AB | IAi group A |
| i | IBi group B | ii group O |
- Offspring: 1 AB : 1 A : 1 B : 1 O
- Probability of blood group O = 1/4, or 25%
8. By using examples, explain how each of the following provides evidence for organic evolution. Give three points for each.
(a) Fossil records
(b) Comparative embryology
Suggested answer and marking guide
(a) Fossil records, any three
- Sequence of life: Older rock layers contain simpler organisms and younger layers contain more complex ones, showing that life changed over time.
- Gradual change within a group: Fossils of the horse show an increase in body size and a reduction in the number of toes from Eohippus to the modern horse.
- Transitional forms: Archaeopteryx had both reptile features (teeth, tail) and bird features (feathers), linking reptiles and birds.
- Extinct organisms: Fossils of species that no longer live, such as dinosaurs, show that organisms have changed or died out.
(b) Comparative embryology, any three
- Similar early embryos: The early embryos of fish, amphibians, reptiles, birds and mammals look alike, which suggests a common ancestor.
- Shared structures: All vertebrate embryos show gill slits and a tail at some stage, even though adult land vertebrates lose them.
- Later divergence: Differences appear only as development continues, and the more closely related two organisms are, the longer their embryos stay similar.
- Example: The human embryo has a tail and pharyngeal pouches, like the embryos of other vertebrates.
SECTION C (30 marks): Answer any two questions
9. You are invited as a guest speaker at a youth meeting to fight against drug abuse. Recommend six preventive and control measures you would address to them.
Suggested answer and marking guide
Measures, any six
- Education and awareness: Teach young people about the harm drugs do to health, family and future.
- Guidance and counselling: Offer counselling in schools, religious groups and communities.
- Strong laws and enforcement: Punish those who make, sell and traffic drugs.
- Rehabilitation: Provide centres that help addicts recover and return to society.
- Creating jobs and income: Give young people skills training and work, so idleness does not push them to drugs.
- Sports and recreation: Provide clubs and activities that keep young people busy and healthy.
- Good role models and parental care: Parents and leaders should set a good example and keep close to their children.
- Controlling availability: Restrict the sale of alcohol and other drugs, especially to young people.
10. Matatu villagers have appointed you as chairperson of a campaign for gonorrhoea prevention. Explain three ways of transmission and five measures that will help them to prevent the disease.
Suggested answer and marking guide
Ways of transmission, any three
- Unprotected sexual contact: Vaginal, anal or oral sex with an infected person passes the bacteria through infected discharges.
- Mother to child: An infected mother can pass the bacteria to the baby's eyes during birth.
- Contact with infected discharge: Touching infected discharge and then touching the eyes or genitals, or sharing contaminated towels or underwear, can pass the bacteria on.
Preventive measures, any five
- Abstain from sex: Not having sex is the surest protection.
- Be faithful: Stay with one uninfected partner.
- Use condoms: Use them correctly every time during sex.
- Avoid multiple partners: This lowers the chance of meeting an infected person.
- Test and treat early: Both partners should be tested and treated if one is infected.
- Screen and treat pregnant women: This protects the baby from infection at birth.
- Education: Teach the community how the disease spreads and how to prevent it.
11. Analyse five environmental factors which affect the rate of transpiration in plants.
Suggested answer and marking guide
Environmental factors
- Light intensity: Bright light opens the stomata wider, so more water vapour escapes. In darkness the stomata close and transpiration falls.
- Temperature: Higher temperature increases evaporation and the kinetic energy of water molecules, so the rate rises.
- Humidity: In dry air the water-vapour gradient between the leaf and the air is steep, so the rate rises. In humid air it falls.
- Wind: Moving air carries away the water vapour near the leaf, keeping the gradient steep and increasing the rate.
- Water supply in the soil: When the soil is dry, the plant cannot replace lost water, the stomata close and the rate falls.
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What are NECTA review papers?
NECTA review papers are past national examination papers, set by the National Examinations Council of Tanzania for the Certificate of Secondary Education Examination (CSEE). Practising them shows you the real exam format and the style of questions.
Which NECTA Biology paper is free on this page?
The free paper is the 2025 CSEE 033/1 Biology 1 paper. The 2010 to 2024 NECTA Biology papers are on the Click Online Academy app on Google Play.
Are the answers on this page the official NECTA marking scheme?
No. The answers on this page were prepared by Click Online Academy for revision and are not the official NECTA marking scheme. If you are unsure about an answer, check it with your Biology teacher.
How do I use the interactive paper?
Choose an option for each multiple-choice question and click Check Answer to see whether you are right and why. For the matching item and written questions, answer on paper first, then click View Answer to see a suggested answer.
How many questions must I answer?
Answer all questions in Sections A and B, and any two of the three questions in Section C. The paper has eleven questions in total and lasts three hours.