insert one dash where needed.\nsalmon hatch in freshwater and migrate to the ocean though they eventually…

insert one dash where needed.\nsalmon hatch in freshwater and migrate to the ocean though they eventually return to freshwater to spawn and die.

insert one dash where needed.\nsalmon hatch in freshwater and migrate to the ocean though they eventually return to freshwater to spawn and die.

Answer

Brief Explanations:

The sentence has a contrast or a break in thought after "ocean" to introduce the opposing idea of returning to freshwater. A dash is needed after "ocean" to show this relationship. So we insert the dash as: "Salmon hatch in freshwater and migrate to the ocean — though they eventually return to freshwater to spawn and die."

Answer:

Salmon hatch in freshwater and migrate to the ocean — though they eventually return to freshwater to spawn and die.