What did Becquerel expect to find when he developed the film from the photographic plates in the drawer? He expected to find one dark spot instead of two. He expected to find no darkening of the film at all. He expected the film to be totally darkened.

he expected to find no darkening of the film all because it hadn't been exposed to sunlight yet.

the population of unionid mussels in the hudson river decreased after zebra mussels were introduced. zebra mussels, a nonnative species, competed with the unionid mussels for food. the zebra mussels were able to outcompete the unionid mussels, allowing the zebra mussel population to increase dramatically over six years. the unionid mussel population decreased due to a lack of food.

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