1.1. Image 2.1 shows a part of the respiratory system where gas exchange takes place.

Image 2.1

Name structures X and Y in Image 2.1. Choose words from the list below.

bronchus alveolus bronchiole trachea

X ……………….........................................……..

Y ……………….........................................……..

1.2. (i) Underline the correct term from the brackets to complete each of the following sentences:

[3]

I. The gas that moves from the air into the bloodstream is

( carbon dioxide / oxygen / nitrogen ).

II. The process that describes how the gas moves from the air into the bloodstream is

( respiration / osmosis / diffusion / photosynthesis ).

III. The process that releases energy in cells is

( respiration / osmosis / diffusion / photosynthesis).

(ii) Describe two ways that the part of the respiratory system shown in Image 2.1 is adapted for gas exchange.

[2]

1.3. Table 2.2 shows the percentage of gases in inspired and expired air

Table 2.2

Complete Table 2.2 by adding the missing percentages to the empty boxes from the list below:

0.04 16 78 21 4