Biology 5090 · O Level · Mammalian sense organs

Mammalian sense organs — practice question

The diagrams show the frontal view of the pupil and iris of the eye at different light intensities. Which row gives the correct description of diagram X?

  • Aeye is in bright light; circular muscles of the iris are relaxed; radial muscles of the iris are contracted
  • Beye is in bright light; circular muscles of the iris are contracted; radial muscles of the iris are relaxed
  • Ceye is in dim light; circular muscles of the iris are relaxed; radial muscles of the iris are contracted
  • Deye is in dim light; circular muscles of the iris are contracted; radial muscles of the iris are relaxed

Worked solution & mark scheme

This 1-mark question has a full step-by-step worked solution and mark scheme.

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI