Referring to areas on the map, describe the spread of the Zika virus between 1947 and 2010.

State what type of diffusion accounts for the spread of the Zika virus from French Polynesia to Brazil.

Explain three health improvements that have led to an increase in life expectancy in many low-income countries in recent years.

Examine the strengths and limitations of the energy efficiency ratio as an indicator of sustainable agriculture.

Award [1] for each of the following, up to a maximum of [3]:

• starts in East/Central Africa, 1947
• spreads to Southeast Asia 1969
• spreads to West Africa 1975
• spreads to Pacific Islands 2007
• spreads to Thailand/Laos/Cambodia/Southeast Asia 2010.

Dates and countries/regions should be identified, if not, award marks as follows:

• 3 correct regions and no dates = 2
• 2 regions and 2 dates = 2
• 2 regions and 1 date = 1
• 2 regions and 0 dates = 1

Relocation.

Award [1] for each valid improvement, and [1] for further development.

For example: Improved access to safe water [1] resulting in a reduction in waterborne diseases, such as cholera and diarrhea [1].

Other possible improvements include:

• incidence of vector-borne diseases, such as malaria, has been reduced by strategies such as bed nets, spraying, clearing of stagnant water
• reduction in sexually transmitted diseases, such as HIV, due to better education, use of condoms
• the rollout of anti-retroviral therapies (ARTs) has increased the life expectancy of people with HIV
• improvements in medical care, numbers of doctors/health professionals; vaccinations
• improvements in food supply, reduced incidences of death from malnutrition.

Energy efficiency ratio is a measure of the amount of energy input into a farming system compared with the energy outputs. A ratio of greater than 1 is considered efficient, as outputs will be greater than inputs. Inputs into the system include labour, machinery, pesticides, fertilizers, irrigation and fuel, while outputs refer to the quantity/yield of food that is produced.

Energy efficiency ratios differ for many farming systems around the world. Capital-intensive systems, such as irrigated rice farming, are likely to have high inputs and high yields, and might be considered as efficient. Subsistence farming systems, with high inputs of labour, might also be regarded as efficient if the outputs are high.

Farming systems differ in their EERs and their relative sustainability. EER might be a good indicator of the efficiency of a farming system, but it neglects the wider environmental and social impacts of farming. Agricultural systems that have a high EER might produce plentiful food supplies, but they are not necessarily sustainable. The farming system might have an adverse impact on the land or water – for example, irrigation might lead to salinization and depletion of groundwater; pesticides might result in eutrophication, and soil quality might be degraded.

Good answers may examine the extent to which EERs are a useful indicator of sustainability in its fullest sense (social, economic and environmental). Another approach might be to examine differing perspectives on the usefulness of the EER relative to other agricultural indicators.

For band D, expect some description of strengths and limitations of EERs.

At band E, expect either a more detailed explanation of the strengths and limitations of EERs, or a structured examination of the value of EERs in relation to sustainable agriculture.

At band F, expect both.

Marks should be allocated according to the Paper 2 HL and SL markbands.