Draw the letter X on Fig. 3.1a to indicate where the damage shown in Fig. 3.1b is located in the person’s skeleton.
Describe the injury to the person’s skeleton shown in Fig. 3.1b.
Name the muscle labelled B in Fig. 3.2.
Draw an arrow on Fig. 3.2 to show the direction of movement that will be caused when the muscle labelled B contracts.
When the muscle labelled B contracts, the muscle labelled A relaxes. State the name of the type of pair of muscles that acts like this.
Using Fig. 3.3, compare the approximate percentage of body mass that comes from the skeleton in birds and in humans.
One reason for this difference is that bird bones contain air spaces. These air spaces are linked to the bird’s lungs. Birds also have a higher haemoglobin concentration per unit volume of blood than humans. Suggest how these adaptations, and the one shown in Fig. 3.3, help a bird move by flying.