A research group is investigating how changing diets affect global land use. Fig. 1 is a food-system flow diagram for a city in China. It shows grain grown ...
Question 1 Report
A research group is investigating how changing diets affect global land use. Fig. 1 is a food-system flow diagram for a city in China. It shows grain grown for people, grain fed to pigs, pork sold through urban markets, and food waste collected for anaerobic digestion. The digester produces biogas and fertiliser. As incomes rise, demand for meat has increased, but the city also wants to reduce methane emissions from landfill and improve food security. Farmers supplying the city face pressure to use water efficiently and avoid fertiliser pollution in rivers.
(a) Identify the animal shown in Fig. 1 that is fed grain. [1]
(b) Describe one output from anaerobic digestion shown in the figure. [1]
(c) Explain two reasons why producing pork can require more resources than eating grain directly. [2]
(d) Explain two ways collecting food waste for digestion can reduce environmental impacts. [2]
(e) Evaluate whether increasing meat consumption always indicates successful development. [3]
Answer Details
(a) The animal fed grain is a pig. [1]
(b) Anaerobic digestion produces biogas or fertiliser, in the form of digestate. [1]
(c) Pigs eat grain that people could eat directly. Energy is lost between trophic levels, so producing pork requires more feed and therefore usually more land, water and other resources than eating grain directly. [2]
(d) Collecting food waste reduces the amount sent to landfill. Digestion captures biogas for energy and reduces methane emissions from rotting waste; its digestate can also replace some manufactured fertiliser. Any two linked benefits gain credit. [2]
(e) Higher meat consumption may reflect higher incomes, greater food choice and access to protein. However, it can increase pressure on land and water and raise emissions. Successful development is better judged through a balanced, lower-waste diet that meets needs sustainably, not simply by more meat consumption. [3]
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