How the School-Based Assessment is marked (skills, marks, investigation, workbook), how Paper 03/2 works for private candidates — then a 60-mark mock 03/2.
6 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.
20% of your grade is decided in the lab, long before exam day. Know exactly what earns the marks.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Copy these into your notebook in your own words — that is how they stick.
School-Based Assessment: 5 skills, 90 raw marks (50 Year 1 + 40 Year 2), weighted to 40 = 20% of the grade.
Private candidates: 2 h 10 min, 3 questions, same skills as the SBA.
Ecology, diffusion/osmosis, photosynthesis/respiration, food tests, germination, nutrition & disease, genetics.
≥ 18 practicals; dated, numbered pages; contents page with asterisks for CXC-assessed practicals.
Proposal (PD, 10) + Implementation (AI, 20 → 10). Students taking two or more sciences may do one investigation only.
A CXC moderator re-marks a sample of five candidates (highest, middle, lowest and midpoints).
P&D work written in the past tense with results included is NOT accepted for SBA.
8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better.
Write full answers, then reveal the mark scheme and tick the points you earned (52 marks in total). Your answers are saved on this device.
Question 1 [20 marks]
Three dishes: X — concentrated salt solution; Y — half that concentration; Z — tap water. Three peeled cucumber slices, 0.5 cm thick, of the same diameter were placed one in each dish for 30 minutes, then patted dry and compared.
(a) Draw up a suitable table of results with correct headings (describe its columns if typing) and the expected observations. [9]
(b) Describe how the solution for Dish Y was made. [2]
(c) State the control and the manipulated variable. [2]
(d) Explain the difference between the slices in Dish X and Dish Z. [2]
(e) State a conclusion, and THREE improvements to give more reliable data. [5]
Question 2 [17 marks]
Two potted plants were enclosed in clear plastic bags tied at the base and weighed every hour in dim light. Percentage water loss: Species P — 0, 4, 7, 9.5, 11, 12, 12.5, 13, 13.5, 13.5, 14 (hours 0–10). Species Q — 0, 8, 10.5, 12, 13.5, 15, 16, 17, 18.5, 19.5, 21.
(a) Describe how you would plot both sets of data on one grid. [8]
(b) Suggest TWO sources of error. [2]
(c) Explain the difference in water loss between the two species. [2]
(d) Describe how the apparatus was set up, and TWO adaptations that reduce water loss. [5]
Question 3 [15 marks]
Woodlice were placed in the centre of a four-part choice chamber: A wet & light, B wet & dark, C dry & light, D dry & dark. Counts at 5 min — A 4, B 14, C 2, D 10; at 20 min — A 1, B 24, C 1, D 4; at 40 min — A 0, B 29, C 0, D 1.
(a) Describe how to set up a simple light/dark investigation with a Petri dish and black paper; state TWO precautions for the woodlice. [4]
(b) State TWO limitations of the investigation. [2]
(c) Suggest the observation that led to the investigation, and a hypothesis. [4]
(d) Using the results, state the conditions woodlice responded to positively and those they avoided, and suggest a natural habitat. [5]
Everything in this lesson is based on these parts of the CXC syllabus and papers.
This lesson’s structured section is a 60-mark mock Paper 03/2. For exam conditions allow 2 h 10 min.