its strange this dino is so small but how do they survive

I understand their bigger then velociraptor meaning their size is around 3ft tall, weight can reach 900lbs and length 8ft long.

While they must have abilities to use for brute strength so they must charge their enemies by tackling like full body attack, their ability of jaw strength must be like 200-1200lbs being bale to break the enemies bones right?

Their skin must be taugh for durable enough to take attacks of velociraptor bites, clawing and sharp talons.

all animals evolve to best fit the niche they occupy. That equally applied to dinosaurs such as Protoceratops.

Also see previous answers to your own questions (using different usernames)
http://www.askabiologist.org.uk/answers … p?id=11351
http://www.askabiologist.org.uk/answers … p?id=11331

This is now your last warning. If you continue to repeatedly asking the same or very similar questions you will be banned form this site permanently.