Choose the correct prepositions to complete the sentences. 1 Scientists have put global warming on / down to industrial pollution. 2 International governments need to set out / on new rules to help protect many animal species. 3 We go over /through a lot of food every week, but we don't throw much off / away. 4.Governments need to speed on /up research into environmental problems. 5 Big companies must pay over / up if they break environmental laws.