You use "it's" as a formal Contraction, it's short for 'it is' or 'it has'.
For example, 'it's a wonderful day's
You use "so" when you are describing something
For example, 'it's so hot'
"So" is also another word for "very", which is where the word originally generated. it's often mixed up with "such", but dont worry! you'll learn English alot soon!
The skin cell is not a eukaryotic cell
The one that could be used to increase the pace of a story is : B. short phrases
Short phrases is very common to be used to increase the pace of the story. You commonly find it in the scene where the character involved in fast-paced action with high tension
hope this helps
