Suggest and explain how the interaction between the muscles labelled in Figure 1 could cause the pupil to constrict (narrow).

The fovea of the eye of an eagle has a high density of cones. An eagle focuses the image of its prey onto the fovea.

Explain how the fovea enables an eagle to see its prey in detail.

Do not refer to colour vision in your answer.

The retina of the human eye has an area of approximately 1.094 × 103 mm2

The circular fovea in a human eye has a diameter of 3 × 103 µm

Calculate the area of the fovea as a percentage of the area of the retina.

The area of a circle is πr2. Use π = 3.14 in your calculation.

Show your working.

Answer ______________ %

The retina of an owl has a high density of rod cells.

Explain how this enables an owl to hunt its prey at night.

Do not refer to rhodopsin in your answer.