Consider the impacts on the bird population and its gene pool. is responsible for gene flow and an important mechanism for genetic variation. a) emigration only b) immigration only c) neither emigration or immigration d) both emigration and immigration

I would say immigration only.

emigration would theoretically reduce the genetic variation as unique individuals leave, but immigration would bring unique traits into circulation in an ecosystem.

I'm not super great at biogy tho so this might not be right... :)

A force can move a stationary object. Ex-The force of engine makes a stationery car to move.