1.1. Figure 4.1 shows the structure of the human gas exchange system.

Figure 4.1

Identify structures V, W, and X in Figure 4.1.

1.2. For Figure 4.1:

(i) Identify one tissue type that is present in structures V, W, and X but not in structure Y.

[1]

(ii) Explain the function of the tissue identified in part (i).

[2]

1.3. Figure 4.2 is an image of a micrograph showing a cross section through structure Y.

Figure 4.2

Explain one structural adaptation visible in Figure 4.2.

1.4. Identify and explain one other feature of structure Y that assists its function.