Which of the following is known as a special interest group?

Republican Party

A special interest group is a society or a group of individuals interested, motivated and driven to a certain goal or outcome. Their primary aim is to achieve a particular goal of changing or improving a certain aspect in a society either involves, academics, science, technology or the society as a whole. 

Correct textbook answers would be 1,3, and 5

The one that most represents the earths mantle would be the skin since the mantle is the upper part of the earths depths which is just like the skin of an apple.