The correct answer is benign tumor
They are not dangerous for you since they're not malignant like cancers. They can become dangerous if they become too large over time, but they're not that big of a deal.
Cardi/o is on of the many root words
Answer: Puberty
Explanation: 13 is an age when most boys have at least started puberty, and my brother got a little bigger from puberty because he had to eat more to feed his growth spurts.