Edexcel IGCSE Biology Graphical and Numerical Forms

Edexcel IGCSE Biology Graphical and Numerical Forms
Edexcel IGCSE Biology syllabusBiology 4BI1Issue 3 (2024)

Practise Edexcel IGCSE Biology graphical and numerical forms by reading graph values, using table categories and describing biological trends.

How this is tested

  • Use graph readings to find biological values such as impulse speed or sweat release rate.
  • Use table categories or data trends to classify BMI or describe pupil diameter changes.

Question 3(b)(ii)

[Maximum number: 2]

The diagram shows a human eye with some structures labelled.

Figure for Question 3(b)(ii) — Edexcel IGCSE Biology

A teacher investigates the effect of light intensity on pupil diameter.

This is the teacher's method.
- cover a student's eyes with a mask
- set the light intensity in the room to a low level
- remove the mask and wait 20 seconds
- record an image of the student's pupil and iris with a camera
- measure the diameter of the pupil on the image using a ruler
- repeat two more times at the same light intensity

The teacher repeats the experiment at different light intensities.
The table shows the teacher's results.

Table for Question 3(b)(ii) — Edexcel IGCSE Biology

With reference to data in the table, describe the effect of increasing light intensity on the diameter of the pupil.