1) of 2) above 3) at 4) on 5) for 6)

1) of 2) above 3) at 4) on 5) for 6) in 7) with

Last month the extent (a) ___ Arctic sea-ice was the lowest ever recorded (b) ___ a January (during the satellite era), (c) ___ temperatures several degrees (d) ___ the long-term average. Researchers hope to gather valuable new insights (e) ___ the region where Earth's climate is changing fastest.