It’s looks great very detailed and well put together.
Sibling rivalry is the jealousy, competition and fighting between siblings.
The correct answer to this question is letter "<span> b: to imply the main idea of the article." </span>in these days we can kindle a fire without any trouble, because we can easily get a match. The purpose of this line from the text in order <span> to imply the main idea of the article.</span>