Match the five required stimuli with sensory examples
Recognise light sound touch temperature and chemicals without confusing input with response.
Section 14.2 · Sense organs
Exam scope and assessment notes
Core and Extended · Biology 0970, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked; human subject-teacher review, supervised practical competence and cumulative assessment remain pending. Cambridge states that IGCSE 0970 has the same subject content as IGCSE 0610, with 9–1 grading. This StudyForA pathway maps the 2026–2028 syllabus only. This 9–1 graded qualification is available only in a limited number of administrative zones. Confirm that your centre can enter you for this code and exam series with Cambridge International. Cambridge has published a separate syllabus for 2029. StudyForA has not reconciled that version yet; this page supports exams in 2026, 2027 and 2028 only.
Before you begin
- Recall receptors, electrical impulses, CNS organisation and the distinction between a stimulus and an effector response.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
A smell receptor responds to molecules from a source. What is the stimulus category?
What you will learn
- Name every required stimulus category
- Separate physical input from resulting action
Match the five required stimuli with sensory examples
Five required inputs: light, sound, touch, temperature and chemicals. The receptor detects the input; movement or secretion is a possible later response. Original teaching model.
| Feature | Meaning |
|---|---|
| Light | Eye receptor example |
| Sound | Ear vibration example |
| Touch and temperature | Distinct sensory inputs in skin examples |
| Chemicals | Smell and taste examples |
Name every required stimulus category
The required stimulus categories are light, sound, touch, temperature and chemicals. Light can stimulate receptor cells in the eye, while sound vibrations stimulate sensory receptors in the ear. These examples connect a kind of environmental input with specialised detecting cells, rather than giving a list of muscle movements.
Touch involves mechanical contact or pressure on an appropriate sensory surface. Temperature receptors respond to thermal changes, which is different from saying that every feeling of contact is a temperature stimulus. A single body region can contain receptors for more than one kind of input without each receptor cell becoming equally sensitive to all categories.
Separate physical input from resulting action
Chemical receptors contribute to smell and taste. The detected chemicals are an input; a later action such as turning towards food or producing a gland secretion is a response. A chemical stimulus is not necessarily a hormone in the blood, and the stimulus categories should not be confused with the electrical impulse used to communicate information.
For an unfamiliar scenario, first identify what changes at the receptor: light level, vibration, contact, temperature or chemical presence. Then name the relevant stimulus category. The description does not require students to perform an experiment on their own senses; the supplied written examples are sufficient to practise the input-to-receptor distinction.
Pause and explain
Which list includes all five required inputs?
Worked example
List all five required sensory stimulus categories.
Show the worked solution
- Include light and sound.
- Add touch, temperature and chemicals.
Answer Light, sound, touch, temperature and chemicals.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
State all five required stimulus categories.
Give me a hint
Include thermal and chemical inputs as well as light sound and contact.
Compare my reasoning
- Light, sound and touch are three categories.
- Temperature and chemicals complete the list.
Light, sound, touch, temperature and chemicals.
Look for these in your work
- Name all five
- Keep categories as inputs
Classify three supplied inputs: vibration reaching ear receptors, contact with skin, and molecules reaching smell receptors.
Give me a hint
Identify the change detected at each receptor.
Compare my reasoning
- Vibration corresponds to sound; contact corresponds to touch.
- The molecules provide a chemical stimulus.
Sound; touch; chemicals, respectively.
Look for these in your work
- Match each scenario
- Separate chemical input from neural signal
A learner lists running as one of the five stimulus categories. Correct the list and the role.
Give me a hint
A movement can be an output rather than a detected input.
Compare my reasoning
- Running is a body action.
- The required inputs are light, sound, touch, temperature and chemicals.
Running is an action, not one of the required stimulus categories. Use light, sound, touch, temperature and chemicals for the five inputs.
Look for these in your work
- Correct input versus action
- Retrieve the complete list
Common mistakes
- Listing only three of the five categories.
- Calling an effector movement the detected stimulus.
What can you explain now?
Which list includes all five required inputs?
Compare with the explanation
Light, sound, touch, temperature and chemicals
All five categories are present.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Name all five stimulus categories and distinguish one input from a later response.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.