25 Turn over 9 The photograph shows a wombat, an animal that lives in dry parts of Australia. Source: © Blue Gum Pictures/Alamy Stock Photo Wombats are herbivores, feeding on grasses, leaves and bark. Wombats also dig in the soil for roots. They have behavioural and physiological adaptations to survive periods of severe drought. The effect of drought on the health of wild wombats was investigated. Changes in body mass, body condition and the chemical constituents of stomach contents and faeces were recorded. These changes were related to the changes in the quality and quantity of the food of wombats. (a) Explain why drought affects the quality and quantity of the food of wombats. 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Measurement Before drought 10 months into drought 14 months into drought 2 months after rain Body condition index ………………………… 0.86 0.76 0.85 Body mass / kg 26.4 25.1 21.2 25.2 Organic matter in stomach / g kg-1 dry matter 946 732 704 822 Mineral ion content in stomach low high high low Moisture content of faeces / g kg-1 wet mass 815 603 522 748 (i) The body condition was expressed as a body condition index (BCI). The BCI can be calculated using the formula BCI = body mass of wombat mass-for-length of wombat (Y) The mass-for-length (Y) of a wombat can be calculated using the formula Y = (body length × 0.73) – 34.5 A wombat before the drought had a body length of 86.4 cm and a mass of 26.4 kg. Calculate the BCI of this wombat. (2) Answer .............................................................. 27 *(ii) Analyse the data to explain the results of this investigation. 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(Total for Question 9 = 13 marks) TOTAL FOR PAPER = 90 MARKS 28 BLANK PAGE