Correct sentence: A bison's fur is thick, so it doesn't get wet.
Other good version: Bison fur is thick and doesn't get wet.
Simple explanation for a 4-year-old (step by step):
- We add 's to "bison" to show the fur belongs to the bison: "bison's fur."
- We use the word so (or and) instead of just a comma. A comma alone makes the sentence unclear.
- Make sure there is no extra space before the period at the end of the sentence.
Short tip: Say it like this: "A bison's fur is thick, so it doesn't get wet."