Suggest and explain how the interaction between the muscles labelled in Figure 1 could cause the pupil to constrict (narrow) - AQA - A-Level Biology - Question 1 - 2020 - Paper 2

The interaction between the circular and radial muscles in the iris plays a crucial role in regulating the size of the pupil. When the circular muscles contract, they pull the edges of the pupil inward, causing it to constrict. At the same time, the radial muscles relax, allowing the circular muscles to exert their full effect without opposition. This coordinated action reduces the amount of light entering the eye, which is beneficial in bright conditions.