Figure 1 shows a simplified diagram of the human eye in cross-section.
Which row in the table gives the function of structure P and structure Q?
Structure P: detects light | Structure Q: controls the amount of light entering the eye
Structure P: focuses light | Structure Q: detects light
Structure P: detects light | Structure Q: carries nerve impulses to the brain
Structure P: refracts light | Structure Q: controls the amount of light entering the eye