Over the period shown in Fig. 4.1, the person carried out each of these actions: P: read the words in a book, Q: read the time on a wall clock, R: looked out of a window at a bird high in the sky. Identify the order in which the person carried out actions P, Q and R. Place P, Q and R in the correct sequence.
At the time labelled H on Fig. 4.1, the lens is changing its shape. Outline, referring to named structures in the eye, how this occurs.
Complete the labels on Fig. 4.2 by naming the two eye parts indicated by the label lines.
Complete Fig. 4.3 so that it shows how the same eye would look in bright light.
State the type of nervous response that occurs when the eye changes from the appearance in Fig. 4.2 to that in Fig. 4.3.
Suggest why this response is important to the person.