Most of the sentences below are run-on sentences. Which sentence is NOT a run-on sentence?
1.The baker made gingerbread cookies and a gingerbread boy jumped off the cookie sheet and no one could catch it.
2.The Mexican Free-Tailed bat is a type of bat it lives in big groups and a famous group lives under a bridge in Austin, Texas.
3.Evidence showed that the island had been hit by a horrible tsunami.
4.It was a time of extreme drought many trees died and many animals suffered.

The first sentence is a run-on, and a pretty bad one, at that. This sentence would've needed to be split into two in order to be grammatically correct.

"The baker made gingerbread cookies. A gingerbread boy jumped off the cookie sheet and no one could catch it."

The second sentence also needs to be split into two to be correct.

The Mexican Free-Tailed bat is a type of bat that lives in big groups. A famous group lives under a bridge in Austin, Texas.

Sentence 4 needs to be separated with a comma or apostrophe.

"It was a time of extreme drought ; many trees died and many animals suffered."

Sentence 3 is the only one that's fine as-is.