The Return of El Nino

CAE Use of English Part 1: Multiple Choice Exercise 5

For questions 1-8, read the text below and decide which answer (A, B, C or D) best fits each gap.
There is an example at the beginning: (0) A methods , B theories, C causes, D consequences

The Return of El Nino

Aside from the seasons, El Nino and its twin, La Nina, are the two largest single (0) C causes of variability in the world's climate from year to year. Both are dictated by shifts in water temperature in the tropical Pacific basin between Australia and South America. (1)...... after the Spanish words for "Christ child" and "the girl" because of their (2)........ to Christmas, they lead to dramatic shifts in the entire system of oceanic and atmospheric factors from air pressure to currents.
A significant rise in sea temperature leads to an El Nino event whereas a fall in temperature leads to La Nina. The cause of the phenomenon is not fully understood but in an El Nino "event" the pool of warm surface water is forced eastwards by the loss of the westerly trade winds. The sea water evaporates, (3)...... in drenching rains over South America, as well as western parts of the United States, such as California. The effects can (4)....... for anything from a few weeks to 18 months, causing extreme weather as far afield as lndia and East Africa. The correlation with global warming is as (5)...... unclear. Archaeological evidence shows El Ninos and La Ninas have been (6)..... for 15,000 years. But scientists are investigating whether climate change is leading to an increase in their intensity or duration.
The weather pattern is already having early and intense effects and El Nino could bring extreme rainfall to parts of east Africa which were last year (7)....... by a cycle of drought and floods. lt's difficult to (8)....... what will happen to the weather in the British lsles, but it will probably add to the likelihood of record-breaking temperatures in the UK.