Total marks: 90 · Duration: 2 hours
Instructions to candidates
- This paper consists of SIX questions in TWO sections. Answer ALL questions.
- Section A has four structured questions. Section B has two essay questions.
- Write your answers in the spaces provided.
- Where appropriate, answers should be illustrated by diagrams.
- You may use a silent, non-programmable calculator.
- In the January 2027 sitting, Paper 02 is hybrid: you read the questions on screen and write your answers in an answer booklet.
Information
- The total mark for this paper is 90. Each question carries 15 marks.
- The marks for each part question are shown in brackets.
- This paper covers the CSEC Human and Social Biology syllabus: living organisms and the environment; life processes and interdependence; heredity and variation; and disease and its impact on humans. It does not repeat any question from Practice Paper A.
Paper
Section A — Structured Questions (60 marks)
Question 1 — Data analysis: exercise and heart rate (15 marks)
A Form 5 student measured her heart rate while resting, during 6 minutes of step-ups, and for 6 minutes of recovery afterwards. Exercise began at 0 minutes and stopped at 6 minutes.
| Time (minutes) | 0 | 2 | 4 | 6 | 8 | 10 | 12 |
|---|---|---|---|---|---|---|---|
| Heart rate (beats per minute) | 70 | 110 | 128 | 132 | 105 | 82 | 72 |
(a) Plot a line graph of heart rate against time. [4 marks]
(b) Describe how the heart rate changed during the exercise and during the recovery period. [3 marks]
(c) Explain why the heart rate increased during the exercise. [3 marks]
(d) Calculate the percentage increase in heart rate from rest to the highest value recorded. [2 marks]
(e) (i) A fitter classmate's heart rate returned to its resting value after only 4 minutes. Suggest why. [2 marks]
(ii) State one long-term effect of regular exercise on the heart. [1 mark]
Question 2 — Nutrition and digestion (15 marks)
(a) Describe how you would test a sample of food for (i) starch and (ii) protein, giving the positive result for each. [4 marks]
(b) A student eats a meal of rice, peas and fish. Name the enzyme that begins the digestion of protein in the stomach, and state the product it forms. [2 marks]
(c) Explain three ways in which the villi of the small intestine are adapted for absorbing digested food. [3 marks]
(d) Name the deficiency disease caused by a lack of (i) vitamin C and (ii) iron, and give one symptom of each. [4 marks]
(e) Explain why a diet low in fibre can lead to constipation. [2 marks]
Question 3 — The eye and coordination (15 marks)
(a) State the function of each of these parts of the eye: the cornea, the lens and the retina. [3 marks]
(b) Explain how the eye changes in order to focus on a distant object. [4 marks]
(c) Give three differences between control by the nervous system and control by the endocrine system. [3 marks]
(d) Explain how drinking alcohol affects the nervous system, and why this makes driving dangerous. [3 marks]
(e) A grandmother can see the hills clearly but cannot read a newspaper. Name her eye defect and the type of lens that corrects it. [2 marks]
Question 4 — Heredity and variation (15 marks)
(a) Give three differences between mitosis and meiosis. [3 marks]
(b) Albinism is controlled by a recessive allele, a. Two parents with normal pigmentation are both carriers (Aa).
(i) Draw a genetic diagram to show the possible genotypes of their children. [3 marks]
(ii) State the probability that their first child will be albino. [1 mark]
(c) Use a genetic diagram to explain why, at each birth, there is an equal chance of having a boy or a girl. [3 marks]
(d) Variation is caused by both genes and the environment. Give one example of each kind of variation in humans, and explain why identical twins can still differ. [3 marks]
(e) Define the term mutation, and give one factor that can increase the rate of mutation. [2 marks]
Section B — Essays (30 marks)
Question 5 — Lifestyle diseases and HIV (15 marks)
(a) Lifestyle diseases such as hypertension, type 2 diabetes and coronary heart disease are now major causes of death in the Caribbean. Discuss the causes of these diseases, how they can be prevented, and their impact on families and the economy. [8 marks]
(b) Explain how HIV weakens the immune system, and why people with AIDS often die of other infections. [4 marks]
(c) A community has an outbreak of gastroenteritis after heavy rains. Describe three actions the health authorities should take. [3 marks]
Question 6 — Human activities and the environment (15 marks)
(a) Discuss the effects of the overuse of pesticides and fertilisers on the environment and on human health. [6 marks]
(b) Describe the main causes of air pollution in Caribbean towns and cities, and the effects of this pollution on health. [5 marks]
(c) Explain how an enhanced greenhouse effect leads to global warming, and give two consequences of global warming for Caribbean islands. [4 marks]