Answer
The Germ Hypothesis predicts that sterilized broth will remain free of cells so long as cells cannot enter the flask past the neck.
The Spontaneous Generation Hypothesis predicts that sterilized broth will fill with cells as they appear with no living precursors, from the components of the broth.
Work Step by Step
The Germ Hypothesis says that cells must come from living cells; sterilized broth, in which cells have been killed by boiling, will be free of cells unless others enter after sterilization.
The Spontaneous Generation Hypothesis says that cells arise from non-living matter, so boiling the broth to kill any cells already in it does not prevent new cells from arising spontaneously.