what is the movement of individuals of the same species into a different habitat called ?
it was asked in the chapter test and how is it immigration?

There is no mistake in the question. 

Immigration is the migration or the movement of an organism to a place (of which it is not a native) in order to settle there during a specified interval. As a result, the population density of that habitat increases.

Immigration can also be defined as the number of individuals of same species that have come into the habitat from elsewhere.