Because they live in cold waters, true seals, such as the harbor seal, have a thicker layer of blubber than eared seals.
(they; live; L:in cold waters, true seals, such as the harbor seal) (they; have; a thicker layer of blubber than eared seals)
they they
live have
L:in cold waters, true seals, such as the harbor seal
a thicker layer of blubber than eared seals