page 09 15. Merlins are small birds of prey which chase and capture skylarks. The effect of skylark song on hunting by merlins was studied. Graph 1 shows the number of successful and unsuccessful attacks on skylarks showing different singing behaviours. Graph 2 shows how the different singing behaviours affected the mean duration of chases by merlins attacking skylarks. Full song Full song Sub-song Sub-song Song behaviour Song behaviour Number of attacks No song No song 0 20 40 60 80 100 120 Mean chase duration (seconds) Graph 1 Graph 2 Successful attack Unsuccessful attack Key 0 10 20 30 40 50 60 Which of the following generalisations about skylark singing behaviour is valid? A No song decreases the number of attacks by merlins and the time they will chase. B No song increases the success of attacks by merlins and the time they will chase. C No song increases the number of attacks by merlins and the time they will chase. D No song decreases the success of attacks by merlins and the time they will chase. [Turn over