Give the correct form of the word in brackets to complete each sentences

Give the correct form of the word in brackets to complete each sentences.
1.A lot toys encourage children's --------------.(imagine)
2.The factory has provided cheaper------------- lately.(produce)
3.Burning coal is an ------------- way of heating a house.Gas is much cheaper.(economy)
4.According to some scientists the earth is losing its outer atmosphere because of -----------.(pollute)
5.She has one of the biggest art ----------- in Britain.(collect)
6.---------------- has caused many so-called man-made disasters.(forest)
7.---------------- often walk through the streets shouting or singing about something they sell.(cry)
8.Gas and oil ------------ always increases in cold weather.(consume)
9.The police are interested in the sudden ------------- of the valuable painting.(appear)
10.he claimes that his -------------- had caused him to become a criminal.(bring up)