Is the group of words a sentence or a run-on sentence?

the animals stood peacefully in the middle of a large field.
a. sentence
b. run on

Have you ever contributed to “social media outrage” (using your social media accounts to boost the anger about a contemporary issue by forwarding it, liking it, etc.) without stopping to think who might’ve originated the message or what the originator’s motives might’ve been? provide example.