Compound Sentences
Comma Splice, Run-On, or Compound Sentence (Correct) Some people believe that aliens don't exist, but I think life on other planets is possible.
Compound Sentence (It's correctly written)
Comma Splice, Run-On, or Compound Sentence (Correct) The fish tank needs cleaned, I don't want to do it.
Comma Splice (needs a conjunction)
Comma Splice, Run-On, or Compound Sentence (Correct) I wish I had a pool in the summer it can get really hot and a pool would be fun.
Run-On (needs a comma and a conjunction)