The literary device used in this sentence is personification, as the seals are given human-like qualities by suggesting that they are swimming freely.
The literary device that seals swam freely through the icy sea is assonance.
alliteration
Not in normal circumstances. A diode is an electonic device that allows current to flow freely in only one direction.
A compass has a magnetized needle that can spin freely.
A compass has a magnetized needle that can spin freely.
Compass
Now that the stalker has been apprehended, the whole neighborhood can breathe freely.
freely permiable membrane allows everything to pass through.
Females were not allowed to freely intermingle with males.
Insulators.
Substances that can freely pass through the plasma membrane must be small and non-polar.
glucose