In pictures of large cities, which compound is largely responsible for the brownish appearance of the smog? A. nitrogen dioxide
B. iron sulfide
C. water vapor
D. carbon monoxide
E. argon

False, as a substance changes from a solid to a liquid and from a liquid to a gas the molecules get farther apart from each other

Ithink iit might be

The population of unionid mussels decreased after zebra mussels were introduced. zebra mussels competed with the unionid mussels for food. the zebra mussels were able to displace the unionid mussels, allowing the zebra mussel population to increase  over the years. the unionid mussel population decreased because  of lack of food.