TEST 268Cambridge Objective IELTS Intermediate · Questions 1–11The Polar Front Jet StreamComplete the summary below.Write NO MORE THAN TWO WORDS for each answer.The Polar Front Jet StreamThe Polar Front Jet Stream is a wind at a height of up to 1 kilometres above the earth's surface. It moves at approximately 2 km per hour during the winter. The direction of movement is caused by the earth's 3. The jet stream is formed where cold polar air meets warm 4 air.It was first identified by 5 in the 1940s. Planes benefit in terms of both 6 but 7 is difficult.Forecasters use jet streams to predict where depressions will form, and whether the British Isles will have potentially destructive 8 or only 9.Global warming may move the jet stream to the 10 in the summer, creating 11 conditions in the British Isles.