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

i hear thunder i feel rain.

a.
simple sentence

b.
compound sentence

c.
run-on sentence

C. run-on sentence

Explanation:  This is considered a run-on sentence, because it’s like having two complete sentences (independent clauses) put together but without connecting them or putting a period (after “thunder”) between them to make them into two separate sentences. So, in that sense, the idea kids of runs on and on without a comma and a conjunction word (such as “and” in this case). An example to correct this: I hear thunder, and I feel rain.

write a five paragraph essay, you were taught to have three body paragraphs. a university essay is more flexible than that, depending on its length and on what it is trying to say. a short university essay may have three body paragraphs, but it may have more.