What is one piece of evidence from "a voyage to the country of the houyhnhnms" that shows the houyhnhnms are more civilized than typical animals? a. they have a language. b. they wear clothes. c. they have a king. d. they know how to sail?

One piece of the evidence is they have a king.
The fact that the Houyhnhnm have king means that they  develop a complex social structure and separate each roles to all creatures within their community.
This means that they already develop a civilization just like its used in human civilization.

Texas’ gulf coastal plains are the western extension of the coastal plain extending from the atlantic ocean to beyond the rio grande. its characteristic rolling to hilly surface covered with a heavy growth of pine and hardwoods extends into east texas. in the increasingly arid west, however, its forests become secondary in nature, consisting largely of post oaks and, farther west, prairies and brushlands.